Interferometer Michelson experiment

A typical noisy light based CRS experiment involves the splitting of a noisy beam (short autocorrelation time, broadband) into identical twin beams, B and B, tlnough the use of a Michelson interferometer. One ami of the interferometer is computer controlled to introduce a relative delay, x, between B and B. The twin beams exit the interferometer and are joined by a narrowband field, M, to produce the CRS-type third order polarization in the sample ([Pg.1209]

Abstract This tutorial shows how fundamental is the role plaid by interferences in many of the physical processes involved in astrophysical signal formating and consequently instmmentation. It is obvious in interferometry. Grating spectroscopy is explained within the same framework as Young experiment, and Fabry-Perot filters are explained as Michelson interferometers.Polarization interferences, used in Lyot filters, are discussed, emphasizing the analogy with echelle gratings. 

Albert Michelson developed the interferometer about 1880 and conducted the Michelson-Morley experiment in 1887, in which it was found that the speed of light is independent of the motion of the source and the observer, this crucial experiment led Einstein to the theory of relativity. Michelson also used the interferometer to create the predecessor of today s length standard based on the wavelength of light. He received the Nobel Prize in 1907 for precision optical instruments and the spectroscopic and metrological investigations carried out with their aid. ... 

One way to understand special relativity is to see how time dilation and Lorentz contraction of objects parallel to motion can be used to explain the null results of the Michelson-Morley [1] experiment, which was performed to measure the velocity of earth in relation to an assumed ether. The result was that the expected influence of such an ether on the velocity of light was not found. Let us now study this double-pass example, where one arm of a Michelson interferometer was perpendicular to the velocity of the earth s surface, while the other... 

Michelson and Morley [50] used an interferometer to measure the speed of light along two orthogonal directions parallel and perpendicular to the earth s orbital speed. They found that the speeds differed by a value somewhere in the range between 5 and 7.5 km/s. Michelson and Morley were extremely surprised because they expected to observe a difference of 30 km/s. At that time they had no plausible explanation for their empirical observation and decided to interpret the outcome of the experiment as a null result no difference in speed along both direction (apparently, the reason for this choice was that Fresnel s theory predicted no difference). 

At the beginning of the twentieth century, there were several isolated voices claiming for a revision of the Michelson-Morley interpretation. Hicks [52] performed a theoretical analysis of the Michelson-Morley experiment and concluded that data were consistent with a somewhat larger magnitude of the difference of speeds. More importantly, he noted that the data followed a periodic curve proportional to cos 20, where angle 0 refers to a rotation of the interferometer relative to the presumed direction of orbital velocity. The functional dependence present in the results is of the form to be expected if there existed E. 

Numerous unsuccessful measurements were made to determine the motion of earth in the ether. These measurements were not able to give results compatible within the framework of classical Newtonian mechanics, even though that the earth has an orbital velocity v0 30,000 m/s (where v0 is velocity of the earth to the ether). In 1887 Michelson and Morley also determined the earth s orbital velocity by their precision interferometer [11], The updated arrangement of Michelson-Morley experiment (M-M experiment) can be seen in Fig. 1. 

Figure 1. An up-to-date arrangement the of Michelson-Morley experiment. Here LASER means the source of light, BS means beamsplitter, Ml and M2 are mirrors on the end of arms, PD is the phase detector (interferometer), and v is the earth s orbital velocity, which is regarded as the inertial motion for short time periods.

The contrast factors (dn / dT)cp and (An / dc)Tp, taken at the wavelength of the readout laser, are the only quantities which must be measured in separate experiments. For this purpose, a Michelson interferometer has been developed, whose mirrors can be scanned over X/2 [43] (Fig. 6). 

In 1887 two American scientists, physicist Albert Michelson and physical chemist Edward Morley, performed an experiment that was designed to detect the motion of Earth through a hypothetical medium known as the luminiferous ether, which was thought to be present throughout space. They made their measurements with a very sensitive optical instrument now called a Michelson interferometer. Their observations showed no indication of movement through the predicted ether. This outcome was unexpected and has become one of the fundamental experimental results in support of the theory of special relativity, developed by Albert Einstein in 1905. 

According to their calculations the Michelson interferometer should have registered a fringe shift of about four-tenths (0.4) of a fringe. Instead, no fringe shift was observed. They were forced to conclude that their experiment had shown that the hypothesis of a stationary, luminiferous ether was not correct. 

The significance of the Michelson-Morley experiment was not assimilated by the scientific community until after Einstein presented his theory. In fact, when Michelson was awarded the Nobel prize in physics in 1907, the first American to receive that honor, it was for his measurements of the standard meter using his interferometer. The ether wind experiment was not mentioned... 

Hanel, R.A., and B.J. Courath, Thermal Emission Spectra of the Earth and Atmosphere Obtained from the Nimbus 4 Michelson Interferometer Experiment. NASA Report X-620-70-244, 1970. 

Thomas Young s in 1803 performed for the first time the classic experiment that demonstrates optical interference the two-slit interference experiment, which appears as an example in many books on optics in order to explain the concept of interference. Young was not the first to report the phenomenon. It had been observed in various forms, such as Newton s rings, Brewster interference, and Michelson interferometer. Young s experiments however mark a point in the history of science. They led the way to the studies of Augustin Fresnel (1816), who introduced the measurement of the wavelength of light and established... 

Today, interferometers are used widely in the alignment system of lithographic exposure tools for coordinating the movement of the exposure stage. In particular, they have found application in high-precision measurements of extremely small distances, between different objects in the exposure tool. Furthermore, interferometric lithography owes its very existence to the Michelson-Morley experiment. 

Fourier transform infrared spectroscopy (FTIR) had its origins in the interferometer developed by Michelson in 1880 and experiments by astrophysicists some seventy years later. A commercial FTIR instrument required development of the laser (1960, by Theodore H. Maiman [1927- ], Hughes Aircraft), refined optics, and computer hardware and software. The Fourier transform takes data collected in time domain and converts them to frequency domain, the normal infrared (IR) spectrum. FTIR provided vasdy improved signal-to-noise ratios allowing routine analyses of microgram samples. 

Here, we consider as an example a possible problem with an interpretation of a classical version of the Michelson-Morley experiment. In the experiment some pieces of bulk matter were rotated. It was expected that when rotating their linear scale would not change and comparing the light propagation in different arms of the interferometer we can judge whether the speed of light is the same in different directions. 

That means that for a proper interpretation of a Michelson-Morley-like experiment with an interferometer built on an atomic bulk matter we need to consider a dynamic model of structure of this kind of matter with a possible violation of relativity. The latter may involve the Planck scale effects, where a certain relation on low-energy fundamental constants can be set. 

Michelson-Morley experiment An experiment, conducted in 1887 by the US physicists Albert Michelson (1852-1931) and Edward Motley (1838-1923), that attempted to measure the velocity of the earth through the ether. Using a modified Michelson interferometer (see illustration) they expected to observe a shift in the interference fringes formed when the instrument was rotated through 90°, showing that the speed of light measured in the direction of the earth s rota-... 

Without going into any further detail, we will mention one other type of interferometer that is encountered in molecular spectroscopy experiments, namely the scanning Michelson interferometer (for detailed descriptions refer to standard textbooks on optics or laser spectroscopy). These are used in so-called Fourier transform spectrometers for high-resolution molecular spectroscopy in the IR such instruments are commonly known as FTIR spectrometers. While rather popular in analytical molecular spectroscopy of IR wavelengths, namely to record, identify and quantify molecular vibrations, they are less suitable in laser chemistry experiments because of the rather long acquisition times required to record... 

The first high-precision experiment of this kind was performed by Michelson and Morley in 1887 using their famous interferometer for velocities n w 30 km/s. This experiment has been repeated again and again by Michelson and Miller between 1902 and 1904 with much higher accuracy but the very same result the speed of light is constant in all inertial frames of reference. 

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