Type Interferometers

The moving mirror in most interferometers is driven by an electromagnetic transducer that operates on principles that are identical to the voice-coil transducer 

Fourier Transform Infrared Spectrometry, Second Edition, by Peter R. Griffiths and James A. de Haseth Copyright 2007 John Wiley Sons, Inc. 

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In an industrial-design FTIR spectrometer, a modified form of the G enzel interferometer is utilized.A geometric displacement of the moving mirrors by one unit produces four units of optical path difference (compared with two units of optical difference for a Michelson type interferometer). The modified Genzel design reduces the time required to scan a spectrum and further reduces the noise effects asstxiated with the longer mirror translation of most interferometers. 

Dyson, J. A transmission-type interferometer microscope. Nature 164, 229... 

Figure 7.3 The structure of the attosecond stability Michelson-type interferometer equipped with a gas cell.

In its basic design, the equipment is similar to a 2-D TL glow-curve system as described previously, but with the addition of a modified Twyman-Green, Michelson type, interferometer between the oven and the photomultiplier. As the sample is heated, the TL signal is recorded while the movable mirror of the interferometer is scanning a given optical path difference in a preset number of steps. The interference pattern corresponding to each one-way scan... 

Alternatives to the presented interferometric configuration are Mach-Zehnder-type interferometers that are also available as integrated optical devices the performance of such optical sensors will be tested for the above application in the near future. 

Fig. 9.23 Schematic diagram of a Mach Zehnder type interferometer.

Figure 9.23 is a schematic of a Mach Zehnder type interferometer the design of which allows for a polarized light beam to be split in two. The ineoming beam with intensity f is divided into two equally intense beam... 

The first category uses a Michelson-type interferometer or similar device, coupled to a specialized microprocessor for calculating the spectrum, while the second category uses filters or a monochromator with a motorized grating that can scan the range of frequencies studied (Figure 10.7). 

Figure 4.64 illustrates the principle of a traveling-wave Michelson-type interferometer as used in our laboratory. Such a wavemeter was first demonstrated in a slightly different version by Hall and Lee [4.67] and by Kowalski et al. [4.72]. The beams Sr of a reference laser and of a laser with unknown wavelength traverse the interferometer on identical paths, but in opposite directions. Both incoming beams are split into two partial beams by... 

Fig. 5.39. (a) Simultaneous line selection and mode selection by a combination of prism selector and Michelson-type interferometer (b) compact arrangement... 

Figure 4.69 illustrates the principle of a traveling-wave Michelson-type interferometer as used in our laboratory. Such a wavemeter was first demonstrated in a slightly different version by Hall and Lee [184] and by Kowalski et al. [190]. The beams 5r of a reference laser and of a laser with unknown wavelength Xx traverse the interferometer on identical paths, but in opposite directions. Both incoming beams are split into two partial beams by the beam splitters BSl and BS2, respectively. One of the partial beams travels the constant path BS1-P-T3-P-BS2 for the reference beam, and in the opposite direction for the beam Bx. The second partial beam travels the variable path BS1-T1-M3-M4-T2-BS2 for 5r, and in the opposite direction for Bx. The moving corner-cube reflectors T1 and T2 are mounted on a carriage, which either travels with wheels on rods or slides on an airtrack. 

Measurement by interferometric sensors with Fabry-Perot-type interferometer. 

The function of an interferometer can be explained best if considering the Michelson-type interferometer shown schematically in Fig. 2.74 (left). Polychromatic fight is separated into two beams by means of a semitransparent mirror. Both beams are unified at the detector after being reflected at the surface of a second mirror. If both beams are of equal length, then there will be no difference between the beams at the input and the output of the interferometer. However, one of the mirrors moves back and forth with an amplitude Ax. Consequently, in each period interference is encountered. If the actual shift... 

The unique part of an FT-IR spectrometer is the Michelson-type interferometer (Fig. 10). Radiation from the source is made parallel and strikes a beam splitter, typ-... 

FIGURE 10 Michelson-type interferometer. Left Source radiation is transmitted and also reflected by a beam splitter to two mirrors. Right Both mirrors reflect radiation back to the beam splitter, where interference occurs. 

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