Optical material diamond

Curtis A (1989) Method UK Patent Application, N 8901759.4 Cutmore N, Eberhard M www.min-eng.com/protected/me02ex Czaja M, Mazurakb Z (1994) Optical Materials 3 95-98 Czaja M (1999) Excited States of Transition Elements, Duszniki Zdroj, Poland, Abstracts, Polish Academy of Science, P09 Davies G (1994) Properties and Growth of Diamonds. Gordon Davies, King s College, London... 

Diamond electrode — Electrode made from - boron-doped diamond or similar doped diamond materials. Diamond, natural or synthetic, exhibits some exceptional material properties such as low thermal expansion, optical transparency for visible, IR, and microwave radiation, mechanical strength, and shock resistance [i]. 

Because the ion-assisted processes enable deposition at temperatures less than 100°C, deposition of diamond like coatings has been attempted on a wide range of substrates, e.g., stainless steel, Copper, ceramics,optical materials (plastics, polymers and polycarbonates),glasses,quartz, sapphire,infrared-transmitting optical materials such as germanium, zinc sulfide and zinc selenide, and a variety of electronic grade materials. Although thin films can be produced... 

Barium and strontium have been incorporated in new materials research. Barium titanate (BaTi03) is used in ceramic capacitors and, when incorporated in tin, makes a material harder than diamond. Crystals of barium titanate are also used in optical materials. Strontium titanate (SrTi03) has such a high refractive index that it sparkles like diamond and is used in less expensive jewelry. 

Diamond is the best optical material available and this lack of absorbance accounts for its unique brightness. However, no diamond is perfect and lattice defects combined with impurities, such as nitrogen and boron, give visible coloration and can also cause luminescence. The high cost of diamond has almost completely restricted its use in optical applications. 

Effect of impurities and Structurai Defects. As seen above, diamond would be the ideal transparent material if it were totally free of impurities, particularly nitrogen, and had a perfect structure. Howeverthese conditions are never completely achieved, and impuritiesand crystal-lattice defects and other obstacles to the free movement of photons affect its transmittance. These obstacles add a number of absorption bands to the two mentioned above, particularly in the IR region as shown in Table 11.4. In spite of this, diamond remciins the best optical material. 

Optical Applications. Although diamond can be considered as the ideal optical material, it has found little applications in optics so far because of its restricted size and high cost. It has been used by NASA as an optical window for the Pioneer Venus spacecraft, clearly a case where cost is secondary to performance.P J... 

DLC is not as good an optical material as single crystal diamond but, as seen above, it has many advantages as a thin coating and is satisfactory in many applications. The following is a review of present and potential optical applications of DLC. 

Diamond is supreme among natural gemstones ia H, RI, and DISP. Table 3 shows the steady improvement ia the sequence of diamond imitations, the aim being to produce a colorless, adequately hard material having closely matching optical properties. The iatroduction of synthetic cubic 2irconia ia 1976 brought about a sufficiently close match. 

Several gemstone species occur in various colors, depending on the presence of impurities or irradiation-induced color centers. Examples are the beryl, comndum, and quart2 families. Quart2 has poor optical properties (RI = 1.55, DISP = 0.013), but becomes of gemological interest when it exhibits attractive colors. Any material can have its color modified by the addition of various impurities synthetic mby, sapphires, and spinel are produced commercially in over 100 colors (2). Synthetic cubic 2irconia has been made in essentially all colors of the spectmm (11), but only the colorless diamond imitation is produced commercially in any quantity. 

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