Multiple beam interference

In the second half of the 20th century, a number of advanced variants of optical microscopy were invented. They include phase-contrast microscopy (invented in France) and multiple-beam interference microscopy (invented in England), methods... 

S. Tolansky, Multiple-Beam Interference Microscopy of Metals, Academic Press, New York, 1970. 

The surface forces apparatus (SEA) can measure the interaction forces between two surfaces through a liquid [10,11]. The SEA consists of two curved, molecularly smooth mica surfaces made from sheets with a thickness of a few micrometers. These sheets are glued to quartz cylindrical lenses ( 10-mm radius of curvature) and mounted with then-axes perpendicular to each other. The distance is measured by a Fabry-Perot optical technique using multiple beam interference fringes. The distance resolution is 1-2 A and the force sensitivity is about 10 nN. With the SEA many fundamental interactions between surfaces in aqueous solutions and nonaqueous liquids have been identified and quantified. These include the van der Waals and electrostatic double-layer forces, oscillatory forces, repulsive hydration forces, attractive hydrophobic forces, steric interactions involving polymeric systems, and capillary and adhesion forces. Although cleaved mica is the most commonly used substrate material in the SEA, it can also be coated with thin films of materials with different chemical and physical properties [12]. 

The diffraction grating monochromator is a specific example of mnltiple beam interference effects. Interference between multiple beams can be generated by both division of amplitude (as in the Fabry-Perot interferometer) or by division of wave front (as in the diffraction grating). (Figures 5.9 and 5.10)... 

Figure 5.9 Multiple-beam interference by division of amplitude.

The phase control makes it possible to modify and translate the interference pattern with a fine subperiod resolution [29,30]. Also, very complex patterns can be formed by combining linearly and circularly polarized beams [31-33] and by using several exposures of the same sample by different patterns. Equation 1 can be recast in the form more convenient for theoretical simulation and visualization of the interference patterns of multiple beams with adjustable phases ... 

The diffraction grating monochromator is a specific example of multiple-beam interference effects. Interference between multiple beams can be generated by both division of... 

Figure 3.11 Multiple-beam interference by division of amplitude. Reprinted with kind permission of Prentice-Hall International.

Illustration of optical phenomena in OLEDs (a) wide-angle interference in noncavity (weak microcavity) OLED (b) wide-angle and multiple-beam interference in strong microcavity OLEDs. (From Wu, C.-C. et al., /. Display Technol, 1,248,2005. With permission.)... 

Examples of devices in which only two partial beams interfere are the Michelson interferometer and the Mach-Zehnder interferometer. Multiple-beam interference is used, for instance, in the grating spectrometer, the Fabry-Perot interferometer, and in multilayer dielectric coatings of highly reflecting mirrors. 

Fig. 4.35. Multiple-beam interference at two plane-parallel partially reflecting surfaces...

G. Koppelniann Multiple beam interference and natural modes in open resonators. Progress in Optics 1 (North-Holland, Amsterdam 1969) pp. 1-66... 

FIGURE 16.67 A satellite repeater receives uplink signals (U), translates them to a downlink frequency band (D), channelizes, amplifies to high power, and retransmits to Earth. Multiple beams allow reuse of the available band. Interference (dashed lines) can limit performance. Downconversion may also occur after the input multiplexers and several intermediate frequencies, and downconversions may be used. 

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