Optical films

H. Angus Macleod, 2001, Thin-Film Optical Filters, Third Edition, ISBN 0 7503 0688 2, loP, Institute of Physics Publishing, Bristol and Philadelphia Alfred Thelen, 1988, Design of Optical Interference Coatings, ISBN 0-07-063786-5, McGraw-Hill Book Compagny... 

While planar optical sensors exist in various forms, the focus of this chapter has been on planar waveguide-based platforms that employ evanescent wave effects as the basis for sensing. The advantages of evanescent wave interrogation of thin film optical sensors have been discussed for both optical absorption and fluorescence-based sensors. These include the ability to increase device sensitivity without adversely affecting response time in the case of absorption-based platforms and the surface-specific excitation of fluorescence for optical biosensors, the latter being made possible by the tuneable nature of the evanescent field penetration depth. 

It should be noted, however, that applicability of the thin-film optic-fiber sensor technology to pipelines for leak detection is still a challenge because pipelines are hundreds (even thousands) mile long. Additional research is needed to identify and develop sensors technologies for hydrogen leak detection along the pipeline. 

Fu, Y. Bryan, N. 2002. One-step transfer of diffractive structure from a designed pattern to a replica by use of a hybrid solgel film. Optics Express 10 436 142. 

Several techniques can be employed to couple an optical beam propagating in free space into a thin-film optical waveguide. Grating coupling and prism coupling (Fig. 15.4) are briefly outlined here, since these methods are applied in actual reverse waveguide and MCLW configurations, respectively. 

From optical point of view, an OLED structure can be considered as a multilayer thin-film system composed of absorbing and nonabsorbing materials, as shown in Figure 6.27. Therefore, the optical properties and optimal structure of such a multilayer device can be investigated by applying thin-film optical analysis techniques. Based on the theory of optical admittance analysis for analyzing the optical properties of a thin-film system [92], the optical properties of an OLED thin-film system can be simulated to reduce the ambient reflection. 

DNOC (4,6-dinitro-o-cresol), 13 283 14 349 DNQ-novolac photoresist film, optical absorption spectrum of, 15 163-164 DNQ-novolac resists, 15 162... 

Hydrogenated cocoglycerides, in cosmetic molded sticks, 7 840t Hydrogenated DGEBA, 10 374-375 Hydrogenated films, optical absorption of, 17 206... 

Interest has developed in electrochromic light transmission modulators, which are called smart windows , for control of temperature and lighting in buildings and automobiles. A cross section of an electrochromic light transmission modulator is shown in Fig. 11.31 (Rauh and Cogan, 1988). The two electrochromic elements of the structure are designated ECl and EC2, and are sandwiched between two thin film, optically transparent, electrodes of ITO and separated by an electrolyte. The ECl layer should colour when a negative potential is applied and the EC2 layer should either colour under positive potentials or remain in a transparent state. This is indicated by the chemical reactions ... 

Abeles, B., and J. I. Gittleman, 1976. Composite material films optical properties and applications, Appl. Opt., 15, 2328-2332. 

There are numerous actual and potential applications for COC in the film, optical, medical, and packaging areas. 

FOSDIC film optical sensing device FT flame temperature... 

An alternative to avoid self-quenching is to use the electrostatic layer-by-layer assembly (ELBL) technique. It eliminates this effect because the indicator is distributed in consecutive (nanometer-thick) polymer layers, each of them having opposite polarity to the previous one. In fact, this technique can be utilized to adsorb the optimum dye concentration with adequate separation in thin film optical sensors [14,15]. 

Fig. 8.18 Total internal reflection thin-film optical switch (after K. Wasa el al. (1984) J. Lightwave Techn. IEEE., LT-2, 710-14).

There are various thin-film optical switch principles based on interference, diffraction or total internal reflection (TIR). The TIR switch, the essentials of which are shown in Fig. 8.18, depends on TIR of light passing from one medium to another of lower refractive index. TIR occurs for small differences in refractive indices when the angle of incidence approaches 90°, i.e. for light almost parallel to the surface of the material with the lower refractive index. 

Macleod HA (1986) Thin-film optical filters. Macmillan, New York... 

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