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Sagnac effect

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705:. However, since the gravitational field would have to be significant, Laue (1920) concluded it is more likely that the effect is a result of changing the distance of the path by its movement through space. "The beam traveling around the loop in the direction of rotation will have farther to go than the beam traveling counter to the direction of rotation, because during the period of travel the mirrors and detector will all move (slightly) toward the counter-rotating beam and away from the co-rotating beam. Consequently the beams will reach the detector at slightly different times, and slightly out of phase, producing optical interference 'fringes' that can be observed and measured." 2773: 123: 2740:
proven performance in the telecom industry, with lifespans measured in decades. However, the assembly of multiple optical components into a precision gyro instrument is costly. Analog FOGs offer the lowest possible cost but are limited in performance; digital FOGs offer the wide dynamic ranges and accurate scale factor corrections required for stringent applications. Use of longer and larger coils increases sensitivity at the cost of greater sensitivity to temperature variations and vibrations.
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and westward around the world. In the case of a Sagnac interferometer a measure of difference in arrival time is obtained by producing interference fringes, and observing the fringe shift. In the case of a relay of pulses around the world the difference in arrival time is obtained directly from the actual arrival time of the pulses. In both cases the mechanism of the difference in arrival time is the same: the Sagnac effect.
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Michelson–Gale experiment was not calibrated by comparison with an outside reference (which was not possible, because the setup was fixed to the Earth). From its design it could be deduced where the central interference fringe ought to be if there would be zero shift. The measured shift was 230 parts in 1000, with an accuracy of 5 parts in 1000. The predicted shift was 237 parts in 1000.
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of motion of the emitting body". Einstein specifically stated that light speed is only constant in the vacuum of empty space, using equations that only held in linear and parallel inertial frames. However, when Einstein started to investigate accelerated reference frames, he noticed that "the principle of the constancy of light must be modified" for accelerating frames of reference.
2345: 644:, i.e. in moving glass) and "the fact that every part of the rotating apparatus runs away from one ray, while it approaches the other one", i.e. the Sagnac effect. He acknowledged that this latter effect alone could cause the time variance and, therefore, "the accelerations connected with the rotation in no way influence the speed of light". 774:, but the result is general for loop geometries with other shapes. If a light source emits in both directions from one point on the rotating ring, light traveling in the same direction as the rotation direction needs to travel more than one circumference around the ring before it catches up with the light source from behind. The time 1986: 63:, the light takes the same amount of time to traverse the ring in either direction. However, when the interferometer system is spun, one beam of light has a longer path to travel than the other in order to complete one circuit of the mechanical frame, and so takes longer, resulting in a phase difference between the two beams. 2562:
that are transported so slowly that time dilation effects arising from the transport are negligible the amount of time difference between the clocks when they arrive back at the starting point will be equal to the time difference that is found for a relay of pulses that travels around the world: 207 nanoseconds.
2752:. Michelson noted the extreme stability of the fringes produced by this form of interferometer: White-light fringes were observed immediately upon alignment of the mirrors. In dual-path interferometers, white-light fringes are difficult to obtain since the two path lengths must be matched to within a couple of 2799:
A variety of competing optical systems are being explored for third generation enhancements beyond Advanced LIGO. One of these competing proposals is based on the zero-area Sagnac design. With a light path consisting of two loops of the same area, but in opposite directions, an effective area of zero
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RLGs require accurate machining, use of precision mirrors, and assembly under clean room conditions. Their mechanical dithering assemblies add somewhat to their weight but not appreciably. RLGs are capable of logging in excess of 100,000 hours of operation in near-room temperature conditions. Their
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Fibre optic gyros (FOGs) and ring laser gyros (RLGs) both operate by monitoring the difference in propagation time between beams of light traveling in clockwise and counterclockwise directions about a closed optical path. They differ considerably in various cost, reliability, size, weight, power, and
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For the sake of simplicity, assume that all emitted photons are emitted in a direction parallel to the ring. Fig. 7 illustrates the effect of the ring laser's rotation. In a linear laser, an integer multiple of the wavelength fits the length of the laser cavity. This means that in traveling back
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Since emitter and detector are traveling at the same speeds, Doppler effects cancel out, so the Sagnac effect does not involve the Doppler effect. In the case of ring laser interferometry, it is important to be aware of this. When the ring laser setup is rotating, the counterpropagating beams undergo
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Fig. 8 illustrates the physical property that makes the ring laser interferometer self-calibrating. The grey dots represent molecules in the laser cavity that act as resonators. Along every section of the ring cavity, the speed of light is the same in both directions. When the ring laser device
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can be obtained; the beat frequency is the difference between the two frequencies. This beat frequency can be thought of as an interference pattern in time. (The more familiar interference fringes of interferometry are a spatial pattern). The period of this beat frequency is linearly proportional to
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Consider a ring interferometer where two counter-propagating light beams share a common optical path determined by a loop of an optical fiber, see Figure 4. The loop may have an arbitrary shape, and can move arbitrarily in space. The only restriction is that it is not allowed to stretch. (The case
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This equation is invalid, however, if the light source's path in space does not follow that of the light signals, for example in the standard rotating platform case (FOG) but with a non-circular light path. In this case the phase difference formula necessarily involves the area enclosed by the light
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was a very large ring interferometer, (a perimeter of 1.9 kilometer), large enough to detect the angular velocity of the Earth. The outcome of the experiment was that the angular velocity of the Earth as measured by astronomy was confirmed to within measuring accuracy. The ring interferometer of the
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which states that gravity and acceleration are equivalent. Spinning or accelerating an interferometer creates a gravitational effect. "There are, however, two different types of such motion; it may for instance be acceleration in a straight line, or circular motion with constant speed." Also, Irwin
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in 1913. Its purpose was to detect "the effect of the relative motion of the ether". Sagnac believed that his results constituted proof of the existence of a stationary aether. However, as explained above, von Laue already showed in 1911 that this effect is consistent with special relativity. Unlike
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is also recognized as a counterpart to Sagnac effect physics. In the actual Hafele–Keating experiment the mode of transport (long-distance flights) gave rise to time dilation effects of its own, and calculations were needed to separate the various contributions. For the (theoretical) case of clocks
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We imagine a screen for viewing fringes placed at the light source (or we use a beamsplitter to send light from the source point to the screen). Given a steady light source, interference fringes will form on the screen with a fringe displacement proportional to the time differences required for the
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below). That is, special relativity in its original formulation was adapted to inertial coordinate frames, not rotating frames. Albert Einstein in his paper introducing special relativity stated, "light is always propagated in empty space with a definite velocity c which is independent of the state
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in 1904. They hoped that with such an interferometer, it would be possible to decide between a stationary aether, versus aethers which are partially or completely dragged by the Earth. That is, if the hypothetical aether were carried along by the Earth (or by the interferometer) the result would be
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A relay of pulses that circumnavigates the Earth, verifying precise synchronization, is also recognized as a case requiring correction for the Sagnac effect. In 1984 a verification was set up that involved three ground stations and several GPS satellites, with relays of signals both going eastward
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This does not contradict special relativity and the above explanation by von Laue that the speed of light is not affected by accelerations. Because this apparent variable light speed in rotating frames only arises if rotating coordinates are used, whereas if the Sagnac effect is described from the
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are displaced compared to their position when the platform is not rotating. The amount of displacement is proportional to the angular velocity of the rotating platform. The axis of rotation does not have to be inside the enclosed area. The phase shift of the interference fringes is proportional to
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To understand what happens in a ring laser cavity, it is helpful to discuss the physics of the laser process in a laser setup with continuous generation of light. As the laser excitation is started, the molecules inside the cavity emit photons, but since the molecules have a thermal velocity, the
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of its frequency. In the case of a ring laser the same applies: the number of cycles of the laser light's frequency is the same in both directions. This quality of the same number of cycles in both directions is preserved when the ring laser setup is rotating. The image illustrates that there is
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Punturo, M.; Abernathy, M.; Acernese, F.; Allen, B.; Andersson, N.; Arun, K.; Barone, F.; Barr, B.; Barsuglia, M.; Beker, M.; Beveridge, N.; Birindelli, S.; Bose, S.; Bosi, L.; Braccini, S.; Bradaschia, C.; Bulik, T.; Calloni, E.; Cella, G.; Chassande Mottin, E.; Chelkowski, S.; Chincarini, A.;
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Interferometric FOGs are purely solid-state, require no mechanical dithering components, do not require precision machining, have a flexible geometry, and can be made very small. They use many standard components from the telecom industry. In addition, the major optical components of FOGs have
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The fringe shift in a Sagnac interferometer due to rotation has a magnitude proportional to the enclosed area of the light path, and this area must be specified in relation to the axis of rotation. Thus the sign of the area of a loop is reversed when the loop is wound in the opposite direction
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In passive ring interferometers, the fringe displacement is proportional to the first derivative of angular position; careful calibration is required to determine the fringe displacement that corresponds to zero angular velocity of the ring interferometer setup. On the other hand, ring laser
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Ring laser gyroscopes suffer from an effect known as "lock-in" at low rotation rates (less than 100°/h). At very low rotation rates, the frequencies of the counter-propagating laser modes become almost identical. In this case, crosstalk between the counter-propagating beams can result in
1545:, whose derivation is based on the constant speed of light. It is evident from this formula that the total time delay is equal to the cumulative time delays along the entire length of fibre, regardless whether the fibre is in a rotating section of the conveyor, or a straight section. 683:
on the Sagnac effect stating, "General relativity would of course be capable of giving some statements about it, and we want to show at first that no noticeable influences of acceleration are expected according to it." He makes a footnote regarding discussions with German physicist,
632:, who claimed the results were at odds with special relativity. This was rebutted by Einstein. Harress himself died during the First World War, and his results were not publicly available until von Laue persuaded Otto Knopf, whose assistant Harress had been, to publish them in 1920. 2475:{\displaystyle \oint \mathbf {v} \cdot d\mathbf {x} =\oint {\boldsymbol {\omega }}\times \mathbf {x} \cdot d\mathbf {x} =\oint {\boldsymbol {\omega }}\cdot \mathbf {x} \times d\mathbf {x} =2\oint {\boldsymbol {\omega }}\cdot d\mathbf {A} =2{\boldsymbol {\omega }}\cdot \mathbf {A} } 627:
of light propagating through moving glass. Not aware of the Sagnac effect, Harress had realized the presence of an "unexpected bias" in his measurements, but was unable to explain its cause. Harress' analysis of the results contained an error, and they were reanalyzed in 1914 by
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is obtained thus canceling the Sagnac effect in its usual sense. Although insensitive to low frequency mirror drift, laser frequency variation, reflectivity imbalance between the arms, and thermally induced birefringence, this configuration is nevertheless sensitive to passing
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fluctuations from the warm air above the match. Sagnac interferometers are almost completely insensitive to displacements of the mirrors or beam-splitter. This characteristic of the Sagnac topology has led to their use in applications requiring exceptionally high stability.
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interferometers do not require calibration to determine the output that corresponds to zero angular velocity. Ring laser interferometers are self-calibrating. The beat frequency will be zero if and only if the ring laser setup is non-rotating with respect to inertial space.
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at frequencies of astronomical interest. However, many considerations are involved in the choice of an optical system, and despite the zero-area Sagnac's superiority in certain areas, there is as yet no consensus choice of optical system for third generation LIGO.
2764:, the Sagnac configuration inherently matches the two path lengths. Likewise Michelson observed that the fringe pattern would remain stable even while holding a lighted match below the optical path; in most interferometers the fringes would shift wildly due to the 2166:
Imagine a screen for viewing fringes placed at the light source (alternatively, use a beamsplitter to send light from the source point to the screen). Given a steady light source, interference fringes will form on the screen with a fringe displacement given by
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Fibre optic gyroscopes are sometimes referred to as 'passive ring interferometers'. A passive ring interferometer uses light entering the setup from outside. The interference pattern that is obtained is a fringe pattern, and what is measured is a phase shift.
2781:(clockwise or anti-clockwise). A light path that includes loops in both directions, therefore, has a net area given by the difference between the areas of the clockwise and anti-clockwise loops. The special case of two equal but opposite loops is called a 1484:. In glass the speed of light is slower than in vacuum, and the optical cable is the moving medium. In that case the relativistic velocity addition rule applies. Pre-relativistic theories of light propagation cannot account for the Fizeau effect. (By 1900 2539: 233: 1503:
The Sagnac effect is well understood in the context of special relativity where from the rotating light source's point of view the phase difference is due to the line of simultaneity along the light path not forming a closed loop in spacetime.
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Likewise, the light traveling in the opposite direction of the rotation will travel less than one circumference before hitting the light source on the front side. So the time for this direction of light to reach the moving source again is:
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An example of the modified configuration is shown in Fig. 5, the measured phase difference in both a standard fibre optic gyroscope, shown on the left, and a modified fibre optic conveyor, shown on the right, conform to the equation
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At non-relativistic speeds, the Sagnac effect is a simple consequence of the source independence of the speed of light. In other words, the Sagnac experiment does not distinguish between pre-relativistic physics and relativistic physics.
1347: 663:(1921). Or when these coordinates are used to compute the global speed of light in rotating frames, different apparent light speeds are derived depending on the orientation, an effect which was shown by Langevin in another paper (1937). 4587:
Eberle, T.; Steinlechner, S.; Bauchrowitz, J. R.; HĂ€ndchen, V.; Vahlbruch, H.; Mehmet, M.; MĂŒller-Ebhardt, H.; Schnabel, R. (2010). "Quantum Enhancement of the Zero-Area Sagnac Interferometer Topology for Gravitational Wave Detection".
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Figure 5. Conceptually, a conventional fibre optic gyro (FOG), shown on the left, can be divided into two semicircular sections with extended fibre connecting the end sections as shown on the right, creating a fibre optic conveyor
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Harress' results were published together with an analysis by von Laue, who showed the role of the Sagnac effect in the experiment. Laue said that in the Harress experiment there was a calculable difference in time due to both the
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The effect is a consequence of the different times it takes right and left moving light beams to complete a full round trip in the interferometer ring. The difference in travel times, when multiplied by the optical frequency
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The Sagnac effect has stimulated a century long debate on its meaning and interpretation, much of this debate being surprising since the effect is perfectly well understood in the context of special relativity.
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Figure 7. Schematic representation of the frequency shift when a ring laser interferometer is rotating. Both the counterpropagating light and the co-propagating light go through 12 cycles of their frequency.
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which was set up to prove an aether wind caused by earth drag, the Sagnac experiment could not prove this type of aether wind because a universal aether would affect all parts of the rotating light equally.
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viewpoint of an external inertial coordinate frame the speed of light of course remains constant – so the Sagnac effect arises no matter whether one uses inertial coordinates (see the formulas in section
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is rotating, then it rotates with respect to that background. In other words: invariance of the speed of light provides the reference for the self-calibrating property of the ring laser interferometer.
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and taking into account the different phase velocities for the different propagation directions in an inertial laboratory frame, which can be calculated using relativistic addition of velocities.
2719:), lock-in will only occur during the brief instances where the rotational velocity is close to zero; the errors thereby induced approximately cancel each other between alternating dead periods. 1093: 1024: 3544: 859: 659:, which results into the so-called Born metric or Langevin metric. From these coordinates, one can derive the different arrival times of counter-propagating rays, an effect which was shown by 2617: 561: 2886: 2485: 179: 3567: 2686: 4658: 2220: 3943:
Wang, R.; Zheng, Y.; Yao, A.; Langley, D (2006). "Modified Sagnac experiment for measuring travel-time difference between counter-propagating light beams in a uniformly moving fiber".
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Einstein was aware of the phenomenon of the Sagnac effect through the earlier experiments of Franz Harress in 1911. Harress' experiment had been aimed at making measurements of the
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predicted that light would slow down in a gravitational field which is why it could predict the curvature of light around a massive body. Under General Relativity, there is the
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paths in space. Some authors refer to this effect as Sagnac effect although in this case the discrepancy need not be due to the lines of simultaneity not forming closed loops.
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along a (not necessarily circular) light path. This configuration introduces another reason for the phase difference: according to the light source the two signals now follow
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that light travels due to the rotation of the ring.(Fig. 3) The simplest derivation is for a circular ring of radius R, with a refractive index of one, rotating at an
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Freise, A.; Chelkowski, S.; Hild, S.; Pozzo, W. D.; Perreca, A.; Vecchio, A. (2009). "Triple Michelson interferometer for a third-generation gravitational wave detector".
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Shapiro in 1964 explained General Relativity saying, "the speed of a light wave depends on the strength of the gravitational potential along its path". This is called the
330: 255: 2854: 2796:, and operated at a power level of about 100 watts of laser power at the beam splitter. After an upgrade to Advanced LIGO several kilowatts of laser power are required. 307: 4219: 1833: 512: 485: 959: 884: 655:). So when the Sagnac effect should be described from the viewpoint of a corotating frame, one can use ordinary rotating cylindrical coordinates and apply them to the 275: 2578:
are extremely sensitive to rotations, which need to be accounted for if an inertial guidance system is to return accurate results. The ring laser also can detect the
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Typically three or more mirrors are used, so that counter-propagating light beams follow a closed path such as a triangle or square (Fig. 1). Alternatively
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could account for the Fizeau effect, but by that time his theory had evolved to a form where in effect it was mathematically equivalent to special relativity.)
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Although this simple derivation is for a circular ring with an index of refraction of one, the result holds true for any shape of rotating loop with area 
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The Sagnac topology was actually first described by Michelson in 1886, who employed an even-reflection variant of this interferometer in a repetition of the
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For more complicated shapes, or other refractive index values, the same result can be derived by calculating the optical phase shift in each direction using
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A. Einstein, 'Generalized theory of relativity', 94; the anthology 'The Principle of Relativity', A. Einstein and H. Minkowski, University of Calcutta, 1920
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can be employed to guide the light through a closed path (Fig. 2). If the platform on which the ring interferometer is mounted is rotating, the
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in 1911, two years before Sagnac conducted his experiment. By continuing the theoretical work of Michelson (1904), von Laue confined himself to an
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The first interferometry experiment aimed at observing the correlation of angular velocity and phase-shift was performed by the French scientist
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of a circular ring interferometer rotating about its center in free space is recovered by taking the index of refraction of the fiber to be 1.)
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Sagnac interferometer. The result is an interferometer that exhibits the stability of the Sagnac topology while being insensitive to rotation.
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light inside the laser cavity is at first a range of frequencies, corresponding to the statistical distribution of velocities. The process of
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can be replaced by those with no moving parts in many modern inertial navigation systems. A conventional gyroscope relies on the principle of
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It is also possible to construct a ring interferometer that is self-contained, based on a completely different arrangement. This is called a
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in 1897 proposed that a giant ring interferometer be constructed to measure the rotation of the Earth; a similar suggestion was made by
4870: 4772: 3253:= 1 - 1/Îœ - (λ/Îœ)(∂Μ /∂λ) , by which the aberration becomes dependent on the movement of the medium, although to only a small degree.) 3239:= 1 - 1/Îœ - (λ/Îœ)(∂Μ/∂λ) bestimmt, bei der die Aberration von der Bewegung der Mittel, wennschon in nur geringem Grade, abhĂ€ngig wird." 2732:
other performance characteristics that need to be considered when evaluating these distinct technologies for a particular application.
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wavelength shift (hence a frequency shift) in such a way that the number of cycles is the same in both directions of propagation.
2010:. In general, the two beams will visit a given segment at slightly different times, but, in the absence of stretching, the length 4838: 3431:
Guido Rizzi; Matteo Luca Ruggiero (2003). "The relativistic Sagnac Effect: two derivations". In G. Rizzi; M.L. Ruggiero (eds.).
55:. The relative phases of the two exiting beams, and thus the position of the interference fringes, are shifted according to the 4875: 4833: 4808: 4400: 4244: 3458: 3055: 2689:
Figure 8. The red and blue dots represent counter-propagating photons, the grey dots represent molecules in the laser cavity.
389:(which he called a "valid" reference frame), and in a footnote he wrote "a system which rotates in respect to a valid system 4948: 4725: 4974: 2945: 1036: 967: 807: 596: 2881: 2583: 2136:{\displaystyle \Delta T=\int \left(dt_{+}-dt_{-}\right)\approx {\frac {2}{c^{2}}}\oint \mathbf {v} \cdot d\mathbf {x} } 746:
The shift in interference fringes in a ring interferometer can be viewed intuitively as a consequence of the different
641: 2602:, need to take the rotation of the Earth into account in the procedures of using radio signals to synchronize clocks. 517: 4843: 4823: 3673:
Michelson, Albert Abraham; Gale, Henry G. (1925). "The Effect of the Earth's Rotation on the Velocity of Light, II".
1737: 2793: 563:. He concluded that this interferometer experiment would indeed produce (when restricted to terms of first order in 4782: 4767: 2644:
makes one frequency quickly outcompete other frequencies, and after that the light is very close to monochromatic.
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When light propagates in fibre optic cable, the setup is effectively a combination of a Sagnac experiment and the
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remains pointing in the same direction after spinning up, and thus can be used as a rotational reference for an
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L.D. Landau, E.M. Lifshitz, (1962). "The Classical Theory of Fields". 2nd edition, Pergamon Press, pp. 296–297.
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Anderson, R.; Bilger, H.R.; Stedman, G.E. (1994). "Sagnac effect: A century of Earth-rotated interferometers".
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Clark, J.; Coccia, E.; Colacino, C.; Colas, J.; Cumming, A.; Cunningham, L.; Cuoco, E.; et al. (2010).
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Udd, E.; Watanabe, S. F.; Cahill, R. F. (1986). "Comparison of ring laser and fiber-optic gyro technology".
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Allan, D. W., Weiss, M. A., & Ashby, N. (1985). "Around-the-World Relativistic Sagnac Experiment".
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On the proof of the reality of the luminiferous aether by the experiment with a rotating interferometer
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frequency shifts in opposite directions. This frequency shift is not a Doppler shift, but is rather an
228:{\displaystyle \Delta \phi \approx {\frac {8\pi }{\lambda c}}{\boldsymbol {\omega }}\cdot \mathbf {A} } 87: 3762: 3385: 2882:"Sur la preuve de la rĂ©alitĂ© de l'Ă©ther lumineux par l'expĂ©rience de l'interfĂ©rographe tournant"  742:
Figure 3. Light traveling opposite directions go different distances before reaching the moving source
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the angular velocity of the ring laser with respect to inertial space. This is the principle of the
4979: 3730: 3276:"Bemerkungen zu P. Harzers Abhandlung 'Über die MitfĂŒhrung des Lichtes in Glas und die Aberration'" 2636:. The light is generated and sustained by incorporating laser excitation in the path of the light. 2571: 2275:{\displaystyle \Delta \phi \approx {\frac {4\pi }{\lambda c}}\oint \mathbf {v} \cdot d\mathbf {x} } 709: 374: 340: 3314: 3275: 1991: 1786: 312: 238: 5005: 3624: 3278:[Comments on P. Harzer's article 'On the entrainment of light in glass and aberration']. 2849: 106:
whereas the sensitivity of the ring interferometer to rotation arises from the invariance of the
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is the distance (black bold arrow in Fig. 3) that the mirror has moved in that same time:
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for light of the wavelength λ as measured in a stationary medium is determined by the formula
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The first description of the Sagnac effect in the framework of special relativity was done by
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where the first factor is the frequency of light. This gives the generalized Sagnac formula
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In Agard Guided Optical Structures in the Military Environment 14 P (See N87-13273 04-74
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Modified versions of the experiment have been proposed with the light source allowed to
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of the apparatus. In other words, when the interferometer is at rest with respect to a
3997: 3974: 5015: 4922: 4787: 4706: 4623: 4451: 4396: 4377: 4324: 4172: 4103: 4061: 3797: 3747: 3739: 3515: 3454: 3413: 3104:"Die Versuche von F. Harreß ĂŒber die Geschwindigkeit des Lichtes in bewegten Körpern" 3051: 2855:
The demonstration of the luminiferous aether by an interferometer in uniform rotation
2749: 2708: 1481: 336: 152: 4520: 4343: 4184: 4115: 3789: 4696: 4686: 4635: 4619: 4615: 4573: 4561: 4506: 4498: 4443: 4365: 4316: 4164: 4095: 4049: 3970: 3925: 3887: 3785: 3735: 3690: 3641: 3619: 3505: 3495: 3405: 3334: 3295: 3216: 3173: 3123: 2999: 2966: 2946:"Experiments on the Absence of Mechanical Connexion between Ether and Matter"  2925: 2814: 2765: 2757: 2743: 2715:
the laser cavity back and forth through a small angle at a rapid rate (hundreds of
2665: 751: 656: 652: 56: 4479:"The third generation of gravitational wave observatories and their science reach" 4251: 3982: 2772: 2647: 2482:
This gives Sagnac formula for ring interferometers of arbitrary shape and geometry
2282:
In the special case that the fiber moves like a rigid body with angular frequency
4420: 4168: 3908:
Anandan, J. (1981). "Sagnac effect in relativistic and nonrelativistic physics".
3708:
Stedman, G. E. (1997). "Ring-laser tests of fundamental physics and geophysics".
1485: 592: 4447: 4099: 3106:[The experiments of F. Harress on the speed of light in moving bodies]. 47:. The Sagnac effect manifests itself in a setup called a ring interferometer or 4053: 3645: 3409: 3235:
fĂŒr Licht von der im ruhenden Mittel gemessenen WellenlĂ€nge λ durch die Formel
2036:
It follows that the time difference for completing a cycle for the two beams is
1493: 611: 604: 107: 64: 40: 36: 4717: 4369: 3891: 3003: 1560:
Fig. 4: A closed optical fiber moving arbitrarily in space without stretching.
514:
of the counter-propagating ray, and consequently obtained the time difference
4994: 4853: 4653: 3659: 3417: 3338: 3299: 3220: 3177: 3127: 2579: 702: 660: 648: 135: 122: 3929: 3392:. The Sagnac effect: 100 years later / L'effet Sagnac : 100 ans aprĂšs. 2880: 2616: 1512: 4710: 4627: 4455: 4328: 4176: 4107: 4077: 3763:"Sagnac effect in a rotating frame of reference. Relativistic Zeno paradox" 3519: 2971: 685: 679:
Max von Laue in his 1920 paper gave serious consideration to the effect of
382: 370: 143: 67:
set up this experiment in 1913 in an attempt to prove the existence of the
3821:
Tartaglia, A.; Ruggiero, M. L. (2004). "Sagnac effect and pure geometry".
3024:
Laue, Max von (1911). "Über einen Versuch zur Optik der bewegten Körper".
1730:
be the length of this small segment in the lab frame. By the relativistic
4320: 3846: 3609:"General Relativity", Lewis Ryder, Cambridge University Press (2009). P.7 2753: 1568:
Consider a small segment of the fiber, whose length in its rest frame is
629: 4691: 3957: 3500: 3241:(According to the electromagnetic theory of light and also according to 1359: 19: 2685: 2629: 2342:
and the line integral can be computed in terms of the area of the loop:
2143:
Remarkably, the time difference is independent of the refraction index
1382:
two counter-rotating beams to traverse the circuit. The phase shift is
3827: 3441: 3317:[Answer to a reply of Paul Harzer (Nr. 4753, pp. 10 and 11)]. 2722: 4586: 2907: 2712: 353:
History of special relativity § Experiments by Fizeau and Sagnac
83: 4418: 4299:
Hariharan, P. (1975). "Sagnac or Michelson–Sagnac interferometer?".
3153: 2987: 2929: 2335:{\textstyle \mathbf {v} ={\boldsymbol {\omega }}\times \mathbf {x} } 4036: 3694: 2570:
The Sagnac effect is employed in current technology. One use is in
2210:{\textstyle \Delta \phi \approx {\frac {2\pi c}{\lambda }}\Delta T} 708:
In 1926, an ambitious ring interferometry experiment was set up by
44: 4602: 4548: 4345:"Influence of Motion of the Medium on the Velocity of Light"  4145:"Around the world atomic clocks:predicted relativistic time gains" 378:
negative, while a stationary aether would give a positive result.
2664:
By bringing the two frequencies of laser light to interference a
2591: 1426:{\displaystyle \Delta \phi ={\frac {2\pi c\,\Delta t}{\lambda }}} 2744:
Zero-area Sagnac interferometer and gravitational wave detection
4275: 4220:"Evaluation of Ring Laser and Fiber Optic Gyroscope Technology" 3430: 3315:"Antwort auf eine Replik Paul Harzers (Nr. 4753, S. 10 und 11)" 3199:[On the entrainment of light in glass and aberration]. 1556: 1363:
Figure 4. The Sagnac area formula applies to any shape of loop.
738: 79: 3545:"Sur la théorie de la relativité et l'expérience de M. Sagnac" 23:
Figure 1. Schematic representation of a Sagnac interferometer.
4475: 3227:"Nach der elektromagnetischen Lichttheorie und auch nach dem 2716: 801:
that it takes to catch up with the light source is given by:
4341: 3197:"Über die MitfĂŒhrung des Lichtes in Glas und die Aberration" 2656:
and forth the laser light goes through an integer number of
671:
below) or rotating coordinates (see the formulas in section
2789: 4022:
Ori, A. (2016). "Generalized Sagnac-Wang-Fizeau formula".
4533: 4419:
Sun, K-X.; Fejer, M.M.; Gustafson, E.; Byer R.L. (1996).
3371:"Volume 6: The Berlin Years: Writings, 1914–1917 page 28" 2620:
Figure 6. Schematic representation of a ring laser setup.
1835:
for traversing the segment in the lab frame are given by
4421:"Sagnac Interferometer for Gravitational-Wave Detection" 3820: 176:
and is given by a formula originally derived by Sagnac:
4659:
Ring-laser tests of fundamental physics and geophysics
4142: 3622:(December 1964). "Fourth Test of General Relativity". 2848: 2310: 2173: 2016: 1740: 1692: 647:
While Laue's explanation is based on inertial frames,
339:, that is, the platform's rotation with respect to an 4245:"Fiber-Optic Gyroscopes Key Technological Advantages" 2488: 2348: 2288: 2223: 2149: 2042: 1994: 1845: 1811: 1789: 1635: 1602: 1574: 1459: 1439: 1388: 1263: 1225: 1107: 1039: 970: 944: 895: 869: 810: 780: 760: 569: 520: 493: 466: 446: 426: 395: 315: 287: 263: 241: 182: 160: 3816: 3814: 4661:(Extensive review by G E Stedman. PDF-file, 1.5 MB) 4395:(Second ed.). Academic Press. pp. 28–29. 3942: 3091:
Die Geschwindigkeit des Lichtes in bewegten Körpern
3072:"Franz Harress - The Mathematics Genealogy Project" 2790:
Laser Interferometer Gravitational-Wave Observatory
2541:If one also allows for stretching one recovers the 1088:{\displaystyle t_{2}={\frac {2\pi R}{c+R\omega }}.} 1019:{\displaystyle t_{1}={\frac {2\pi R}{c-R\omega }}.} 3263:List of scientific publications by Albert Einstein 3231:schen RelativitĂ€tsprinzipe wird aber der Wert von 3097:] (in German). Erfurt, Germany: Georg Richter. 2533: 2474: 2334: 2296: 2274: 2209: 2155: 2135: 2025: 2002: 1980: 1827: 1797: 1775: 1722: 1678: 1621: 1588: 1465: 1445: 1425: 1341: 1246: 1208: 1087: 1018: 953: 927: 878: 854:{\displaystyle t_{1}={\frac {2\pi R+\Delta L}{c}}} 853: 793: 766: 583: 555: 506: 479: 452: 432: 408: 324: 301: 269: 249: 227: 168: 4217: 4211: 3989: 3811: 2736:lasers have relatively high power requirements. 1433:, which causes fringes to shift in proportion to 4992: 3618: 3353:"Otto Knopf - The Mathematics Genealogy Project" 1776:{\textstyle d\ell '=\gamma d\ell \approx d\ell } 556:{\displaystyle \Delta \tau =\tau _{+}-\tau _{-}} 4747: 3245:principle of relativity, however, the value of 3032:On an Experiment on the Optics of Moving Bodies 2985: 2878: 2846: 3840: 3838: 3565: 3542: 4733: 4667:"Relativity in the Global Positioning System" 4384: 4292: 3672: 3476:"Relativity in the Global Positioning System" 3151: 3023: 2942: 1679:{\displaystyle dt'_{\pm }={n \over c}d\ell '} 4342:Michelson, A. A. & Morley, E.W. (1886). 4203:: CS1 maint: multiple names: authors list ( 4128:: CS1 maint: multiple names: authors list ( 3754: 3701: 361:of 1887 had suggested that the hypothetical 117: 4469: 3907: 3835: 4740: 4726: 4580: 4527: 4414: 4412: 4236: 3903: 3901: 4902:Tests of relativistic energy and momentum 4700: 4690: 4664: 4601: 4547: 4510: 4390: 4298: 4035: 3956: 3868:E.J. Post (April 1967). "Sagnac effect". 3867: 3826: 3729: 3509: 3499: 3473: 3440: 3435:. Dordrecht: Kluwer Academic Publishers. 2970: 2874: 2872: 2842: 2840: 2776:Figure 9. Zero-area Sagnac interferometer 2680: 1410: 928:{\displaystyle \Delta L=R\omega t_{1}.\,} 924: 440:, and setting the rotational velocity as 4073: 4071: 3383: 3312: 3273: 3147: 3145: 3143: 3141: 3139: 2771: 2684: 2646: 2615: 2163:and the velocity of light in the fiber. 1555: 1511: 1496:resonance effect, as explained below in 1358: 737: 121: 18: 4839:Lorentz-violating neutrino oscillations 4409: 3898: 3760: 3707: 3590:On the Electrodynamics of Moving Bodies 3088: 3041: 3039: 3019: 3017: 3015: 3013: 2519: 2460: 2438: 2405: 2375: 2320: 2297:{\displaystyle {\boldsymbol {\omega }}} 2290: 1988:correct to first order in the velocity 1783:correct to first order in the velocity 213: 169:{\displaystyle {\boldsymbol {\omega }}} 162: 4993: 4242: 3194: 2869: 2837: 2760:of the white light). However, being a 1507: 420:valid". Assuming constant light speed 4907:Kaufmann–Bucherer–Neumann experiments 4876:Experimental testing of time dilation 4834:Antimatter tests of Lorentz violation 4809:Modern searches for Lorentz violation 4721: 4143:Hafele J., Keating, R. (1972-07-14). 4068: 4017: 4015: 3467: 3424: 3136: 3101: 3045: 2988:"Relative Motion of Earth and Aether" 2794:Michelson–Fabry–PĂ©rot interferometers 2582:, which can also be termed "mode 1". 961:from the two equations above we get: 672: 640:(which follows from the relativistic 257:is the oriented area of the loop and 4335: 3936: 3036: 3010: 1805:of the segment. The time intervals 90:. With the development of so-called 4975:Test theories of special relativity 4021: 3386:"Georges Sagnac: A life for optics" 3095:The speed of light in moving bodies 2584:Global navigation satellite systems 1723:{\textstyle d\ell =|d\mathbf {x} |} 460:, he computed the propagation time 367:was completely dragged by the Earth 16:Relativistic effect due to rotation 13: 4012: 2489: 2224: 2201: 2174: 2043: 1411: 1389: 1264: 1108: 945: 896: 870: 839: 521: 316: 309:, determines the phase difference 183: 98:based on the Sagnac effect, bulky 14: 5027: 4933:Michelson–Gale–Pearson experiment 4844:Lorentz-violating electrodynamics 4824:Experiments of Rayleigh and Brace 4646: 3995: 3844: 3357:www.genealogy.math.ndsu.nodak.edu 3076:www.genealogy.math.ndsu.nodak.edu 2565: 718:Michelson–Gale–Pearson experiment 642:velocity addition in moving media 335:The rotation thus measured is an 39:, is a phenomenon encountered in 4886:Length contraction confirmations 4783:de Sitter double star experiment 3384:Darrigol, Olivier (2014-12-01). 2527: 2468: 2449: 2424: 2413: 2394: 2383: 2364: 2353: 2328: 2312: 2268: 2257: 2129: 2118: 1996: 1974: 1951: 1900: 1888: 1791: 1711: 1497: 607:) would give a negative result. 243: 221: 104:conservation of angular momentum 4269: 4218:Juang, J.-N.; Radharamanan, R. 4136: 3861: 3790:10.1070/pu2002v045n08abeh001225 3666: 3652: 3612: 3603: 3594: 3582: 3568:"Sur l'expĂ©rience de M. Sagnac" 3559: 3536: 3527: 3377: 3363: 3345: 3306: 3267: 3256: 3188: 3184:On the Experiment of F. Harress 2548: 1247:{\displaystyle R\omega =v\ll c} 595:). He also concluded that only 35:, named after French physicist 4954:Refutations of emission theory 4793:Measurements of neutrino speed 4620:10.1103/PhysRevLett.104.251102 4512:11858/00-001M-0000-0011-2EAE-2 3082: 3064: 2979: 2936: 2901: 2605: 1716: 1703: 138:in a single or multiple loops. 1: 4566:10.1088/0264-9381/26/8/085012 4536:Classical and Quantum Gravity 4503:10.1088/0264-9381/27/8/084007 4483:Classical and Quantum Gravity 3975:10.1016/S0375-9601(03)00575-9 3433:Relativity in Rotating Frames 2830: 2792:(LIGO) consisted of two 4-km 733: 668: 4949:Refutations of aether theory 4871:Moessbauer rotor experiments 4773:Moessbauer rotor experiments 4768:Kennedy–Thorndike experiment 4169:10.1126/science.177.4044.166 3154:"Zum Versuch von F. Harress" 2033:is the same for both beams. 2003:{\displaystyle \mathbf {v} } 1798:{\displaystyle \mathbf {v} } 694:Theory of General Relativity 688:. The reason for looking at 599:models (such as the ones of 325:{\displaystyle \Delta \phi } 250:{\displaystyle \mathbf {A} } 112:inertial frames of reference 73:theory of special relativity 7: 4763:Michelson–Morley experiment 4749:Tests of special relativity 4448:10.1103/PhysRevLett.76.3053 4100:10.1126/science.228.4695.69 2808: 2675:inertial navigation systems 617:Michelson–Morley experiment 387:inertial frame of reference 369:. To test this hypothesis, 359:Michelson–Morley experiment 134:, can be realized using an 10: 5032: 4829:Trouton–Rankine experiment 4054:10.1103/physreva.94.063837 3740:10.1088/0034-4885/60/6/001 3646:10.1103/PhysRevLett.13.789 3588:Albert Einstein. (1905). 3410:10.1016/j.crhy.2014.09.007 3110:. 4th series (in German). 3026:MĂŒnchener Sitzungsberichte 2762:common-path interferometer 2701: 2609: 1622:{\displaystyle dt'_{\pm }} 350: 346: 302:{\displaystyle c/\lambda } 130:Sagnac interferometer, or 88:inertial navigation system 4962: 4941: 4915: 4894: 4881:Hafele–Keating experiment 4852: 4801: 4755: 4370:10.2475/ajs.s3-31.185.377 3892:10.1103/RevModPhys.39.475 3871:Reviews of Modern Physics 3675:The Astrophysical Journal 3319:Astronomische Nachrichten 3280:Astronomische Nachrichten 3201:Astronomische Nachrichten 3004:10.1080/14786440409463244 2572:inertial guidance systems 2559:Hafele–Keating experiment 1828:{\displaystyle dt_{\pm }} 1356:is the area of the ring. 728: 507:{\displaystyle \tau _{-}} 480:{\displaystyle \tau _{+}} 277:the wavelength of light. 118:Description and operation 4980:Standard-Model Extension 4866:Ives–Stilwell experiment 4819:Trouton–Noble experiment 4814:Hughes–Drever experiment 3339:10.1002/asna.19141990304 3300:10.1002/asna.19141990104 3221:10.1002/asna.19141982001 3178:10.1002/andp.19203671303 3128:10.1002/andp.19203671302 3046:Pauli, Wolfgang (1981). 2986:Michelson, A.A. (1904). 2879:Sagnac, Georges (1913), 2847:Sagnac, Georges (1913), 2673:, widely used in modern 954:{\displaystyle \Delta L} 879:{\displaystyle \Delta L} 375:Albert Abraham Michelson 341:inertial reference frame 270:{\displaystyle \lambda } 4590:Physical Review Letters 4428:Physical Review Letters 4250:. iXSea. Archived from 3930:10.1103/physrevd.24.338 3761:Malykin, G. B. (2002). 3625:Physical Review Letters 3566:Langevin, Paul (1937). 3543:Langevin, Paul (1921). 3390:Comptes Rendus Physique 3089:Harress, Franz (1912). 2723:Fibre optic gyroscopes 1596:. The time intervals, 1589:{\displaystyle d\ell '} 1466:{\displaystyle \omega } 1098:The time difference is 767:{\displaystyle \omega } 673:§ Reference frames 615:the carefully prepared 453:{\displaystyle \omega } 4970:One-way speed of light 4393:Optical Interferometry 4391:Hariharan, P. (2003). 3152:Laue, Max von (1920). 2992:Philosophical Magazine 2972:10.1098/rsta.1897.0006 2943:Lodge, Oliver (1897). 2777: 2690: 2681:Zero point calibration 2652: 2621: 2545:interference formula. 2535: 2476: 2336: 2298: 2276: 2211: 2157: 2137: 2027: 2004: 1982: 1837:Lorentz transformation 1829: 1799: 1777: 1724: 1680: 1623: 1590: 1561: 1518: 1467: 1447: 1427: 1364: 1343: 1248: 1210: 1089: 1020: 955: 929: 880: 855: 795: 768: 743: 692:is because Einstein's 585: 557: 508: 481: 454: 434: 410: 326: 303: 271: 251: 229: 170: 139: 96:fiber optic gyroscopes 24: 4778:Resonator experiments 4280:. McDonnell-Douglas. 3313:Einstein, A. (1914). 3274:Einstein, A. (1914). 3195:Harzer, Paul (1914). 3182:English translation: 3030:English translation: 2951:Philos. Trans. R. Soc 2820:Fiber optic gyroscope 2775: 2727:ring laser gyroscopes 2688: 2650: 2619: 2610:Further information: 2576:Ring laser gyroscopes 2536: 2477: 2337: 2299: 2277: 2212: 2158: 2138: 2028: 2005: 1983: 1830: 1800: 1778: 1725: 1681: 1624: 1591: 1559: 1515: 1468: 1448: 1428: 1362: 1344: 1249: 1211: 1090: 1021: 956: 930: 881: 856: 796: 794:{\displaystyle t_{1}} 769: 741: 698:equivalence principle 586: 558: 509: 482: 455: 435: 411: 409:{\displaystyle K^{0}} 327: 304: 272: 252: 230: 171: 132:fibre optic gyroscope 125: 100:mechanical gyroscopes 49:Sagnac interferometer 22: 5011:Theory of relativity 4321:10.1364/AO.14.2319_1 3048:Theory of Relativity 2825:Ring laser gyroscope 2671:ring laser gyroscope 2634:ring laser gyroscope 2612:Ring laser gyroscope 2486: 2346: 2308: 2286: 2221: 2171: 2147: 2040: 2014: 1992: 1843: 1809: 1787: 1738: 1690: 1633: 1600: 1572: 1457: 1437: 1386: 1261: 1223: 1105: 1037: 968: 942: 893: 867: 808: 778: 758: 597:complete-aether-drag 567: 518: 491: 464: 444: 424: 393: 313: 285: 261: 239: 180: 158: 148:interference fringes 43:that is elicited by 5001:Physics experiments 4895:Relativistic energy 4692:10.12942/lrr-2003-1 4683:2003LRR.....6....1A 4671:Living Rev. Relativ 4612:2010PhRvL.104y1102E 4558:2009CQGra..26h5012F 4495:2010CQGra..27h4007P 4440:1996PhRvL..76.3053S 4362:1886AmJS...31..377M 4313:1975ApOpt..14.2319H 4307:(10): 2319_1–2321. 4286:1986gosm.agar.....U 4161:1972Sci...177..166H 4092:1985Sci...228...69A 4046:2016PhRvA..94f3837O 3998:"Sagnac and Fizeau" 3967:2003PhLA..312....7W 3922:1981PhRvD..24..338A 3884:1967RvMP...39..475P 3847:"The Sagnac Effect" 3782:2002PhyU...45..907M 3722:1997RPPh...60..615S 3687:1925ApJ....61..140M 3660:"The Sagnac Effect" 3638:1964PhRvL..13..789S 3501:10.12942/lrr-2003-1 3492:2003LRR.....6....1A 3480:Living Rev. Relativ 3451:2003gr.qc.....5084R 3402:2014CRPhy..15..789D 3331:1914AN....199...47E 3292:1914AN....199....8E 3213:1914AN....198..377H 3170:1920AnP...367..448L 3120:1920AnP...367..389K 3050:. New York: Dover. 2963:1897RSPTA.189..149L 2922:1994AmJPh..62..975A 2802:gravitational waves 2642:stimulated emission 2026:{\textstyle d\ell } 1651: 1618: 1508:Generalized formula 584:{\displaystyle v/c} 363:luminiferous aether 82:mounted mechanical 75:makes superfluous. 33:Sagnac interference 4858:Length contraction 4802:Lorentz invariance 4665:Ashby, N. (2003). 3474:Ashby, N. (2003). 3158:Annalen der Physik 3108:Annalen der Physik 3102:Knopf, O. (1920). 2778: 2691: 2653: 2622: 2531: 2472: 2332: 2304:, the velocity is 2294: 2272: 2207: 2153: 2133: 2023: 2000: 1978: 1825: 1795: 1773: 1732:length contraction 1720: 1676: 1639: 1619: 1606: 1586: 1562: 1519: 1463: 1443: 1423: 1376:Fermat's principle 1365: 1339: 1254:, this reduces to 1244: 1206: 1085: 1016: 951: 925: 876: 851: 791: 764: 744: 690:General Relativity 681:General Relativity 581: 553: 504: 477: 450: 430: 406: 322: 299: 267: 247: 225: 166: 140: 25: 4988: 4987: 4928:Sagnac experiment 4923:Fizeau experiment 4788:Hammar experiment 4654:The Sagnac Effect 4434:(17): 3053–3056. 4402:978-0-12-311630-7 4155:(4044): 166–168. 4024:Physical Review A 3945:Physics Letters A 3460:978-0-486-64152-2 3057:978-0-486-64152-2 2750:Fizeau experiment 2709:injection locking 2586:(GNSSs), such as 2516: 2251: 2199: 2156:{\displaystyle n} 2112: 1965: 1937: 1919: 1663: 1482:Fizeau experiment 1446:{\displaystyle A} 1421: 1334: 1306: 1201: 1080: 1011: 849: 638:dragging of light 433:{\displaystyle c} 365:, if it existed, 337:absolute rotation 210: 153:angular frequency 61:nonrotating frame 5023: 4742: 4735: 4728: 4719: 4718: 4714: 4704: 4694: 4640: 4639: 4605: 4584: 4578: 4577: 4551: 4531: 4525: 4524: 4514: 4473: 4467: 4466: 4464: 4462: 4425: 4416: 4407: 4406: 4388: 4382: 4381: 4356:(185): 377–386. 4347: 4339: 4333: 4332: 4296: 4290: 4289: 4273: 4267: 4266: 4264: 4262: 4256: 4249: 4240: 4234: 4233: 4231: 4229: 4224: 4215: 4209: 4208: 4202: 4194: 4192: 4191: 4140: 4134: 4133: 4127: 4119: 4075: 4066: 4065: 4039: 4019: 4010: 4009: 4007: 4005: 3993: 3987: 3986: 3960: 3940: 3934: 3933: 3905: 3896: 3895: 3865: 3859: 3858: 3856: 3854: 3842: 3833: 3832: 3830: 3818: 3809: 3808: 3806: 3804: 3767: 3758: 3752: 3751: 3733: 3705: 3699: 3698: 3670: 3664: 3663: 3656: 3650: 3649: 3620:Irwin I. Shapiro 3616: 3610: 3607: 3601: 3598: 3592: 3586: 3580: 3579: 3563: 3557: 3556: 3540: 3534: 3531: 3525: 3523: 3513: 3503: 3471: 3465: 3464: 3444: 3428: 3422: 3421: 3381: 3375: 3374: 3367: 3361: 3360: 3349: 3343: 3342: 3310: 3304: 3303: 3271: 3265: 3260: 3254: 3224: 3192: 3186: 3181: 3149: 3134: 3131: 3098: 3086: 3080: 3079: 3068: 3062: 3061: 3043: 3034: 3029: 3021: 3008: 3007: 2983: 2977: 2976: 2974: 2948: 2940: 2934: 2933: 2905: 2899: 2898: 2884: 2876: 2867: 2866: 2852: 2844: 2815:Born coordinates 2766:refractive index 2758:coherence length 2540: 2538: 2537: 2532: 2530: 2522: 2517: 2515: 2507: 2499: 2481: 2479: 2478: 2473: 2471: 2463: 2452: 2441: 2427: 2416: 2408: 2397: 2386: 2378: 2367: 2356: 2341: 2339: 2338: 2333: 2331: 2323: 2315: 2303: 2301: 2300: 2295: 2293: 2281: 2279: 2278: 2273: 2271: 2260: 2252: 2250: 2242: 2234: 2216: 2214: 2213: 2208: 2200: 2195: 2184: 2162: 2160: 2159: 2154: 2142: 2140: 2139: 2134: 2132: 2121: 2113: 2111: 2110: 2098: 2093: 2089: 2088: 2087: 2072: 2071: 2032: 2030: 2029: 2024: 2009: 2007: 2006: 2001: 1999: 1987: 1985: 1984: 1979: 1977: 1966: 1964: 1963: 1954: 1949: 1938: 1930: 1925: 1921: 1920: 1918: 1917: 1908: 1907: 1903: 1891: 1885: 1880: 1858: 1857: 1834: 1832: 1831: 1826: 1824: 1823: 1804: 1802: 1801: 1796: 1794: 1782: 1780: 1779: 1774: 1751: 1729: 1727: 1726: 1721: 1719: 1714: 1706: 1685: 1683: 1682: 1677: 1675: 1664: 1656: 1647: 1628: 1626: 1625: 1620: 1614: 1595: 1593: 1592: 1587: 1585: 1472: 1470: 1469: 1464: 1452: 1450: 1449: 1444: 1432: 1430: 1429: 1424: 1422: 1417: 1399: 1348: 1346: 1345: 1340: 1335: 1333: 1332: 1323: 1312: 1307: 1305: 1304: 1295: 1291: 1290: 1274: 1253: 1251: 1250: 1245: 1215: 1213: 1212: 1207: 1202: 1200: 1199: 1198: 1189: 1188: 1176: 1175: 1165: 1161: 1160: 1144: 1139: 1138: 1126: 1125: 1094: 1092: 1091: 1086: 1081: 1079: 1065: 1054: 1049: 1048: 1025: 1023: 1022: 1017: 1012: 1010: 996: 985: 980: 979: 960: 958: 957: 952: 934: 932: 931: 926: 920: 919: 885: 883: 882: 877: 860: 858: 857: 852: 850: 845: 825: 820: 819: 800: 798: 797: 792: 790: 789: 773: 771: 770: 765: 752:angular velocity 710:Albert Michelson 657:Minkowski metric 653:Born coordinates 590: 588: 587: 582: 577: 562: 560: 559: 554: 552: 551: 539: 538: 513: 511: 510: 505: 503: 502: 486: 484: 483: 478: 476: 475: 459: 457: 456: 451: 439: 437: 436: 431: 415: 413: 412: 407: 405: 404: 331: 329: 328: 323: 308: 306: 305: 300: 295: 276: 274: 273: 268: 256: 254: 253: 248: 246: 234: 232: 231: 226: 224: 216: 211: 209: 201: 193: 175: 173: 172: 167: 165: 92:laser gyroscopes 71:that Einstein's 57:angular velocity 5031: 5030: 5026: 5025: 5024: 5022: 5021: 5020: 4991: 4990: 4989: 4984: 4958: 4937: 4911: 4890: 4856: 4848: 4797: 4751: 4746: 4649: 4644: 4643: 4585: 4581: 4532: 4528: 4474: 4470: 4460: 4458: 4423: 4417: 4410: 4403: 4389: 4385: 4340: 4336: 4297: 4293: 4274: 4270: 4260: 4258: 4257:on 5 March 2012 4254: 4247: 4243:Napolitano, F. 4241: 4237: 4227: 4225: 4222: 4216: 4212: 4196: 4195: 4189: 4187: 4141: 4137: 4121: 4120: 4086:(4695): 69–71. 4076: 4069: 4020: 4013: 4003: 4001: 3994: 3990: 3958:physics/0609222 3941: 3937: 3906: 3899: 3866: 3862: 3852: 3850: 3843: 3836: 3819: 3812: 3802: 3800: 3770:Physics-Uspekhi 3765: 3759: 3755: 3710:Rep. Prog. Phys 3706: 3702: 3671: 3667: 3658: 3657: 3653: 3632:(26): 789–791. 3617: 3613: 3608: 3604: 3599: 3595: 3587: 3583: 3564: 3560: 3541: 3537: 3532: 3528: 3472: 3468: 3461: 3429: 3425: 3382: 3378: 3369: 3368: 3364: 3351: 3350: 3346: 3311: 3307: 3272: 3268: 3261: 3257: 3207:(20): 377–392. 3193: 3189: 3164:(13): 448–463. 3150: 3137: 3114:(13): 389–447. 3087: 3083: 3070: 3069: 3065: 3058: 3044: 3037: 3022: 3011: 2998:(48): 716–719. 2984: 2980: 2941: 2937: 2930:10.1119/1.17656 2916:(11): 975–985. 2906: 2902: 2877: 2870: 2845: 2838: 2833: 2811: 2746: 2729: 2704: 2683: 2614: 2608: 2568: 2551: 2526: 2518: 2508: 2500: 2498: 2487: 2484: 2483: 2467: 2459: 2448: 2437: 2423: 2412: 2404: 2393: 2382: 2374: 2363: 2352: 2347: 2344: 2343: 2327: 2319: 2311: 2309: 2306: 2305: 2289: 2287: 2284: 2283: 2267: 2256: 2243: 2235: 2233: 2222: 2219: 2218: 2185: 2183: 2172: 2169: 2168: 2148: 2145: 2144: 2128: 2117: 2106: 2102: 2097: 2083: 2079: 2067: 2063: 2059: 2055: 2041: 2038: 2037: 2015: 2012: 2011: 1995: 1993: 1990: 1989: 1973: 1959: 1955: 1950: 1948: 1929: 1913: 1909: 1899: 1898: 1887: 1886: 1884: 1873: 1869: 1865: 1853: 1849: 1844: 1841: 1840: 1819: 1815: 1810: 1807: 1806: 1790: 1788: 1785: 1784: 1744: 1739: 1736: 1735: 1715: 1710: 1702: 1691: 1688: 1687: 1668: 1655: 1643: 1634: 1631: 1630: 1610: 1601: 1598: 1597: 1578: 1573: 1570: 1569: 1551:Stokes' theorem 1510: 1458: 1455: 1454: 1438: 1435: 1434: 1400: 1398: 1387: 1384: 1383: 1371:.(Fig. 4) 1328: 1324: 1313: 1311: 1300: 1296: 1286: 1282: 1275: 1273: 1262: 1259: 1258: 1224: 1221: 1220: 1194: 1190: 1184: 1180: 1171: 1167: 1166: 1156: 1152: 1145: 1143: 1134: 1130: 1121: 1117: 1106: 1103: 1102: 1066: 1055: 1053: 1044: 1040: 1038: 1035: 1034: 997: 986: 984: 975: 971: 969: 966: 965: 943: 940: 939: 915: 911: 894: 891: 890: 868: 865: 864: 826: 824: 815: 811: 809: 806: 805: 785: 781: 779: 776: 775: 759: 756: 755: 736: 731: 669:§ Theories 573: 568: 565: 564: 547: 543: 534: 530: 519: 516: 515: 498: 494: 492: 489: 488: 487:of one ray and 471: 467: 465: 462: 461: 445: 442: 441: 425: 422: 421: 400: 396: 394: 391: 390: 355: 349: 314: 311: 310: 291: 286: 283: 282: 262: 259: 258: 242: 240: 237: 236: 220: 212: 202: 194: 192: 181: 178: 177: 161: 159: 156: 155: 151:the platform's 120: 17: 12: 11: 5: 5029: 5019: 5018: 5013: 5008: 5006:Interferometry 5003: 4986: 4985: 4983: 4982: 4977: 4972: 4966: 4964: 4960: 4959: 4957: 4956: 4951: 4945: 4943: 4939: 4938: 4936: 4935: 4930: 4925: 4919: 4917: 4913: 4912: 4910: 4909: 4904: 4898: 4896: 4892: 4891: 4889: 4888: 4883: 4878: 4873: 4868: 4862: 4860: 4850: 4849: 4847: 4846: 4841: 4836: 4831: 4826: 4821: 4816: 4811: 4805: 4803: 4799: 4798: 4796: 4795: 4790: 4785: 4780: 4775: 4770: 4765: 4759: 4757: 4756:Speed/isotropy 4753: 4752: 4745: 4744: 4737: 4730: 4722: 4716: 4715: 4662: 4656: 4648: 4647:External links 4645: 4642: 4641: 4596:(25): 251102. 4579: 4526: 4468: 4408: 4401: 4383: 4334: 4301:Applied Optics 4291: 4268: 4235: 4210: 4135: 4067: 4011: 3996:Brown, Kevin. 3988: 3935: 3916:(2): 338–346. 3897: 3878:(2): 475–493. 3860: 3845:Brown, Kevin. 3834: 3810: 3776:(8): 907–909. 3753: 3731:10.1.1.128.191 3716:(6): 615–688. 3700: 3695:10.1086/142879 3665: 3651: 3611: 3602: 3593: 3581: 3572:Comptes Rendus 3558: 3549:Comptes Rendus 3535: 3526: 3466: 3459: 3423: 3376: 3362: 3344: 3305: 3266: 3255: 3225:From p. 377: 3187: 3135: 3133: 3132: 3081: 3063: 3056: 3035: 3009: 2978: 2935: 2900: 2891:Comptes Rendus 2868: 2859:Comptes Rendus 2835: 2834: 2832: 2829: 2828: 2827: 2822: 2817: 2810: 2807: 2745: 2742: 2728: 2721: 2703: 2700: 2682: 2679: 2666:beat frequency 2607: 2604: 2567: 2566:Practical uses 2564: 2550: 2547: 2529: 2525: 2521: 2514: 2511: 2506: 2503: 2497: 2494: 2491: 2470: 2466: 2462: 2458: 2455: 2451: 2447: 2444: 2440: 2436: 2433: 2430: 2426: 2422: 2419: 2415: 2411: 2407: 2403: 2400: 2396: 2392: 2389: 2385: 2381: 2377: 2373: 2370: 2366: 2362: 2359: 2355: 2351: 2330: 2326: 2322: 2318: 2314: 2292: 2270: 2266: 2263: 2259: 2255: 2249: 2246: 2241: 2238: 2232: 2229: 2226: 2206: 2203: 2198: 2194: 2191: 2188: 2182: 2179: 2176: 2152: 2131: 2127: 2124: 2120: 2116: 2109: 2105: 2101: 2096: 2092: 2086: 2082: 2078: 2075: 2070: 2066: 2062: 2058: 2054: 2051: 2048: 2045: 2022: 2019: 1998: 1976: 1972: 1969: 1962: 1958: 1953: 1947: 1944: 1941: 1936: 1933: 1928: 1924: 1916: 1912: 1906: 1902: 1897: 1894: 1890: 1883: 1879: 1876: 1872: 1868: 1864: 1861: 1856: 1852: 1848: 1822: 1818: 1814: 1793: 1772: 1769: 1766: 1763: 1760: 1757: 1754: 1750: 1747: 1743: 1718: 1713: 1709: 1705: 1701: 1698: 1695: 1674: 1671: 1667: 1662: 1659: 1654: 1650: 1646: 1642: 1638: 1617: 1613: 1609: 1605: 1584: 1581: 1577: 1537: = 2 1509: 1506: 1494:optical cavity 1462: 1442: 1420: 1416: 1413: 1409: 1406: 1403: 1397: 1394: 1391: 1350: 1349: 1338: 1331: 1327: 1322: 1319: 1316: 1310: 1303: 1299: 1294: 1289: 1285: 1281: 1278: 1272: 1269: 1266: 1243: 1240: 1237: 1234: 1231: 1228: 1217: 1216: 1205: 1197: 1193: 1187: 1183: 1179: 1174: 1170: 1164: 1159: 1155: 1151: 1148: 1142: 1137: 1133: 1129: 1124: 1120: 1116: 1113: 1110: 1096: 1095: 1084: 1078: 1075: 1072: 1069: 1064: 1061: 1058: 1052: 1047: 1043: 1027: 1026: 1015: 1009: 1006: 1003: 1000: 995: 992: 989: 983: 978: 974: 950: 947: 936: 935: 923: 918: 914: 910: 907: 904: 901: 898: 875: 872: 862: 861: 848: 844: 841: 838: 835: 832: 829: 823: 818: 814: 788: 784: 763: 735: 732: 730: 727: 612:Georges Sagnac 580: 576: 572: 550: 546: 542: 537: 533: 529: 526: 523: 501: 497: 474: 470: 449: 429: 403: 399: 348: 345: 321: 318: 298: 294: 290: 266: 245: 223: 219: 215: 208: 205: 200: 197: 191: 188: 185: 164: 119: 116: 108:speed of light 65:Georges Sagnac 41:interferometry 37:Georges Sagnac 31:, also called 15: 9: 6: 4: 3: 2: 5028: 5017: 5014: 5012: 5009: 5007: 5004: 5002: 4999: 4998: 4996: 4981: 4978: 4976: 4973: 4971: 4968: 4967: 4965: 4961: 4955: 4952: 4950: 4947: 4946: 4944: 4940: 4934: 4931: 4929: 4926: 4924: 4921: 4920: 4918: 4916:Fizeau/Sagnac 4914: 4908: 4905: 4903: 4900: 4899: 4897: 4893: 4887: 4884: 4882: 4879: 4877: 4874: 4872: 4869: 4867: 4864: 4863: 4861: 4859: 4855: 4854:Time dilation 4851: 4845: 4842: 4840: 4837: 4835: 4832: 4830: 4827: 4825: 4822: 4820: 4817: 4815: 4812: 4810: 4807: 4806: 4804: 4800: 4794: 4791: 4789: 4786: 4784: 4781: 4779: 4776: 4774: 4771: 4769: 4766: 4764: 4761: 4760: 4758: 4754: 4750: 4743: 4738: 4736: 4731: 4729: 4724: 4723: 4720: 4712: 4708: 4703: 4698: 4693: 4688: 4684: 4680: 4676: 4672: 4668: 4663: 4660: 4657: 4655: 4651: 4650: 4637: 4633: 4629: 4625: 4621: 4617: 4613: 4609: 4604: 4599: 4595: 4591: 4583: 4575: 4571: 4567: 4563: 4559: 4555: 4550: 4545: 4542:(8): 085012. 4541: 4537: 4530: 4522: 4518: 4513: 4508: 4504: 4500: 4496: 4492: 4489:(8): 084007. 4488: 4484: 4480: 4472: 4457: 4453: 4449: 4445: 4441: 4437: 4433: 4429: 4422: 4415: 4413: 4404: 4398: 4394: 4387: 4379: 4375: 4371: 4367: 4363: 4359: 4355: 4351: 4346: 4338: 4330: 4326: 4322: 4318: 4314: 4310: 4306: 4302: 4295: 4287: 4283: 4279: 4272: 4253: 4246: 4239: 4221: 4214: 4206: 4200: 4186: 4182: 4178: 4174: 4170: 4166: 4162: 4158: 4154: 4150: 4146: 4139: 4131: 4125: 4117: 4113: 4109: 4105: 4101: 4097: 4093: 4089: 4085: 4081: 4074: 4072: 4063: 4059: 4055: 4051: 4047: 4043: 4038: 4033: 4030:(6): 063837. 4029: 4025: 4018: 4016: 3999: 3992: 3984: 3980: 3976: 3972: 3968: 3964: 3959: 3954: 3951:(1–2): 7–10. 3950: 3946: 3939: 3931: 3927: 3923: 3919: 3915: 3911: 3904: 3902: 3893: 3889: 3885: 3881: 3877: 3873: 3872: 3864: 3848: 3841: 3839: 3829: 3828:gr-qc/0401005 3824: 3817: 3815: 3799: 3795: 3791: 3787: 3783: 3779: 3775: 3771: 3764: 3757: 3749: 3745: 3741: 3737: 3732: 3727: 3723: 3719: 3715: 3711: 3704: 3696: 3692: 3688: 3684: 3680: 3676: 3669: 3661: 3655: 3647: 3643: 3639: 3635: 3631: 3627: 3626: 3621: 3615: 3606: 3597: 3591: 3585: 3577: 3573: 3569: 3562: 3554: 3550: 3546: 3539: 3530: 3524:(Open access) 3521: 3517: 3512: 3507: 3502: 3497: 3493: 3489: 3485: 3481: 3477: 3470: 3462: 3456: 3452: 3448: 3443: 3442:gr-qc/0305084 3438: 3434: 3427: 3419: 3415: 3411: 3407: 3403: 3399: 3395: 3391: 3387: 3380: 3372: 3366: 3358: 3354: 3348: 3340: 3336: 3332: 3328: 3324: 3321:(in German). 3320: 3316: 3309: 3301: 3297: 3293: 3289: 3285: 3282:(in German). 3281: 3277: 3270: 3264: 3259: 3252: 3248: 3244: 3240: 3236: 3232: 3228: 3222: 3218: 3214: 3210: 3206: 3203:(in German). 3202: 3198: 3191: 3185: 3179: 3175: 3171: 3167: 3163: 3159: 3155: 3148: 3146: 3144: 3142: 3140: 3129: 3125: 3121: 3117: 3113: 3109: 3105: 3100: 3099: 3096: 3092: 3085: 3077: 3073: 3067: 3059: 3053: 3049: 3042: 3040: 3033: 3027: 3020: 3018: 3016: 3014: 3005: 3001: 2997: 2993: 2989: 2982: 2973: 2968: 2964: 2960: 2956: 2952: 2947: 2939: 2931: 2927: 2923: 2919: 2915: 2911: 2904: 2896: 2892: 2888: 2883: 2875: 2873: 2864: 2860: 2856: 2851: 2843: 2841: 2836: 2826: 2823: 2821: 2818: 2816: 2813: 2812: 2806: 2803: 2797: 2795: 2791: 2786: 2784: 2774: 2770: 2767: 2763: 2759: 2755: 2751: 2741: 2737: 2733: 2726: 2720: 2718: 2714: 2710: 2699: 2695: 2687: 2678: 2676: 2672: 2667: 2662: 2659: 2649: 2645: 2643: 2637: 2635: 2631: 2626: 2618: 2613: 2603: 2601: 2597: 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Retrieved 4431: 4427: 4392: 4386: 4353: 4349: 4337: 4304: 4300: 4294: 4277: 4271: 4259:. Retrieved 4252:the original 4238: 4226:. Retrieved 4213: 4199:cite journal 4188:. Retrieved 4152: 4148: 4138: 4124:cite journal 4083: 4079: 4027: 4023: 4002:. Retrieved 3991: 3948: 3944: 3938: 3913: 3910:Phys. Rev. D 3909: 3875: 3869: 3863: 3851:. Retrieved 3801:. 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Index


Georges Sagnac
interferometry
rotation
interference
angular velocity
nonrotating frame
Georges Sagnac
aether
theory of special relativity
gimbal
gyroscope
inertial navigation system
laser gyroscopes
fiber optic gyroscopes
mechanical gyroscopes
conservation of angular momentum
speed of light
inertial frames of reference

guided wave
fibre optic gyroscope
optical fiber
fiber optics
interference fringes
angular frequency
absolute rotation
inertial reference frame
History of special relativity § Experiments by Fizeau and Sagnac
Michelson–Morley experiment

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