Optically equivalent

Photonic crystals have been hailed as the optical equivalent of semiconductors. Eli Yablonovitch at Bell Communications Research first developed the idea of such crystals in the 1980s. 

Building type Number of buildings Number of Samples Asbestos structure and fiber concentrations Optical equivalents Asbestos structures (f/mL) Fibers " (f/mL) (f/mL)" ... 

Fig. 8.8. Differential cross section at 30 and 90 for electron—hydrogen elastic scattering below the n = 2 threshold. Experiment, Williams (1976f>) solid curve, coupled channels optical (equivalent local) (McCarthy and Shang, 1992). From McCarthy and Shang (1992).

Fig. 8.12. Differential cross section for the 1 S, 2 S and 2 P states of helium and electron impact coherence parameters (8.40) for the 2 P state at Eo=50 eV. Experimental data for differential cross sections are 1 S, Register, Trajmar and Srivastava (1980) 2 S,2 P, Cartwright et al. (1992). Experimental data for electron impact coherence parameters are crosses, McAdams et al. (1980) squares, Beijers et al. (1987) plus signs, Eminyan et al. (1974). Solid curves, coupled channels optical (equivalent local) (McCarthy et al., 1991) broken curve, distorted-wave Born (Cartwright et al, 1992). From McCarthy et al (1991).

Table 8.8. Total cross sections for electron-helium scattering. CCO, coupled-channels-optical (equivalent local) method (McCarthy et al.,1991) experiment. Nickel et al. (1985). Units are KT cmi ...

V., Patel, M., Romig, B. W., and Seitzman, J. M. "Optical Equivalence Ratio Sensors for Gas Turbine Combustors." Proceedings of the Combustion Institute 30 (2005) 1601-9. 

These descriptions are suitable as long as it is realized that in most instances elements with bounding surfaces normal to fibril axes are only apparent and not basic. (One exception will be cited below in Section V, 1.) Diffraction evidence favors the assumption that the primary structural cleavage of collagen fibrils is longitudinal, continuing down to elements of protofibrillar thinness, resolvable only by means of wide-angle diffraction. The nearest electron optical equivalent of this evidence is now summarized. 

The additivity of the Stokes parameters allows us to generalize the principle of optical equivalence (Section 7) to quasi-monochromatic light as follows it is impossible by means of a traditional optical instrument to distinguish between various ineoherent mixtures of quasi-monochromatie beams that form a beam with the same Stokes parameters (/, Q, U, V). For example, there is only one kind of unpolarized light, although it can be eomposed of quasi-monoehromatic beams in an infinite variety of optically indistinguishable ways. 

The Mueller-Jones matrix provides a complete description of the anisotropy properties of an object [9,10]. However, the information in the matrix is in implicit form. The history of the problem of analysis of the Jones and Mueller-Jones matrix goes back to the derivation of three equivalence theorems by Hurwitz and Jones [17]. According to the first theorem, an optical system (object) composed of any number of retardation plates (that is an object with linear phase anisotropy) and rotators (circular phase anisotropy) is optically equivalent to a system containing only two elements a retardation plate, and a rotator. The second theorem is analogous to the first and but is concerned with partial polarizers (linear amplitude anisotropy) and rotators. The third theorem claims that an optical system composed of any number of partial polarizers, retardation plates, and rotators is optically equivalent to a system containing only four elements two retardation plates, a partial polarizer, and rotator. 

A common alternative configuration is the optically equivalent combination of a spherical with a plane mirror, a semi-confocal cavity. This is more convenient in that the length of the cavity is reduced by a factor of two, but it does mean doubling the number of reflections and therefore the transmission loss for a given transit path of the radiation through the sample. 

In the case of optoelectronics, the aim is to utilise light in an analogous role to electrons. The optical equivalents to transistors are photonic crystals. These structures interact with light in controlled and predetermined ways. Many are based on... 

Optical bistability is a third-order effect that occurs when a material with an intensity-dependent refractive index can yield two possible states for a single input intensity. This corresponds to the optical equivalent of the transistor. Although much attention has been given to all-optical computing, it is questionable whether such a devise can economically compete with ever cost-decreasing, performance-increasing modern electronic computers, at least in the... 

One of two basic principles is employed in most commercial optical non-contact methods. The first is the laser-focusing technique, which works according to the same basic principle as a CD-player, and can best be described as an optical equivalent of the stylus... 

It is impossible by means of any instrument to distinguish between various incoherent superpositions of wave fields, having the same frequency, that may together form a beam with the same Stokes parameters. This is known as the principle of optical equivalence. 

The structural elements of SONET, and the way they are combined to create a complete SONET signal, are shown in Fig. 15.15. A complete, optically transmitted SONET signal is called an OC-N, where OC is optical carrier and N may be 1, 3, 12, 24, 48, or 192. The OC-N is the optical equivalent of the STS-N where STS is synchronous transport signal. The STS-N or OC-N consists of a multiplex ofN STS-Is. 

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