Mach Zehnder type interferometer

Interferometers separate a laser beam into two beams and then recombine them to create a signal whose intensity depends on the phase difference between them. When a particle with a refractive index greater than that of the surrounding liquid passes through the beam the wave front is retarded and when a gas microbubble passes through it the wave front is advanced. The magnitude of the phase signal depends on particle size and the pulse can be calibrated with particles of known size. 

The variation of the polarization ratio with time has been used to determine the droplet size distribution in fuel sprays. Although polarization ratio is generally applied to an assembly of droplets it can be used for single droplets provided the incident beam is circularly polarized [194] 

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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 TSI Liquitrak interferometer [195-197] uses a dual beam interferometer to detect slight differences in the refractive indices of particles relative to the surrounding media. It is less sensitive to vibration than the Mach Zehnder type of interferometer beeause it does not separate the two light beams. Instead the beams are overlapped and polarized at 90° to each other, hence the beams do not interfere and are effectively separated from each other until combined by the second beam splitter. The narrow separation of the beams reduces vibration sensitivity dramatically because any vibration interference affects both beams equally. 

Fig. 9.71 (a) Paths of the atom in a Mach-Zehnder-type atomic interferometer (b) momentum transfer by stimulated Raman transitions applied to rubidium atoms in an atomic fountain where the atoms move parallel to the laser beams [1291] (c) level scheme for Raman transitions... 

Figure 2.74. Functional principle of interferometers. Left Michelson type, right Mach-Zehnder type...

Based on the way the interferometer is configured, CCMI sensors can be categorized into two groups, namely the Mach-Zehnder interferometer (MZI) type and the Michelson interferometer (MI) type. The MZI sensor works in transmission mode, i.e., the transmitted interference signal is detected. The MI sensor works in reflection mode, where the light passes the interferometer twice and the reflected interference signal is detected. 

Fig. 8 Different types of interferometers - (a-d) Mach-Zehnder - (a) ion-exchange, (b) channelized, (c) ribbed, (d) ARROW, (e-h) Young - (e) using beam splitter for beam combining, (f) using lens for beam combining, (g, h) using dispersion for beam overlap in a side-by-side configuration, and (h) a sandwich configuration...

Two types of interferometers, Fabry-Perot and Mach-Zehnder, have been applied to the study of convection in horizontal fluid layers. 

Many types of interferometry can be used for this purpose. For instance, the Twyman-Green interferometer [11] is suitable for surface testing in reflection. The Mach-Zehnder interferometer permits lens testing in transmission [12]. The third interferometric technique utilizes a Shack-Hartmann wave-front sensor [10,13,14]. This method can be applied to both reflection and transmission. Interestingly, the Shack-Hartmaim sensor utilizes a microlens array in front of a CCD imager array to create a series of focal spots that are recorded by the CCD imager to obtain the wavefront. 

For chemical sensing, interferometers in integrated optics became particularly useful. Of these, the integrated Mach-Zehnder interferometer type predominates. This instrument is considered in Sect. 2.4. 

We know of many types of optical interferometer (the simple double-slit Young interferometer, the Mach-Zehnder interferometer, the Fabry-Perot interferometer, the Talbot interferometer, etc.). A similar situation occurs in atom interferometry. Artificial laboratory devices exploit various types of structure for atom interferometry both material bodies (slits and gratings) and nonmaterial light structures. All these atom interferometers will be considered very briefly we refer readers for details to the book by Berman (1997) and reviews by Baudon et al. (1999), Kasevich (2002), and Chu (2002). 

Furthermore, Shimada and Furukawa [28] measured simultaneously the radius and thickness of a circular disk using a Mach-Zehnder interferometer. They found that there are two types of disk growth before morphological instability of the disk shape. They also observed an asymmetric disk pattern with respect to the basal... 

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