Diamond optical properties

The luminescence of diamonds is related to various defects in its structure. Almost always, luminescence centers in diamonds are related to N atoms. It is logical, because the atomic radii of C and N are nearly equal (approximately 0.77 A). Luminescence spectroscopy has proven to be the most widely used method in studies of diamonds even in comparison with optical absorption, ESR, IR and Raman spectroscopies. Himdreds of spectra have been obtained, fluorescence characteristics enter into diamond quality gemological certificates, a wide range of electronic and laser applications are based on diamond optical properties in excited states nitrogen center aggregation is controlled by the residence time of diamond in the mantle, distinction between natural... 

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. 

Optical Properties. The high refractive index (2.42 at 589.3 nm) and dispersion (0.044) are the basis for the brilliance and fire of a properly cut gemstone. The optical transmission out to 10.6 p.m for Type Ila diamonds makes possible windows for CO2 lasers and for devices such as were in the... 

Optical. Besides the gem quaHties dependent on optical properties, diamond is very useful as a light-transmitting window for lasers and for simple windows for monitoring chemical processes in corrosive and otherwise hostile environments. 

CL is a powerful tool for the characterization of optical properties of wide band-gap materials, such as diamond, for which optical excitation sources are not readily available. 

As mentioned earlier, CL is a powerful tool for the characterization of optical properties of wide band-gap materials, such as diamond, for which optical excitation sources are not readily available. In addition, electron-beam excitation of solids may produce much greater carrier generation rates than typical optical excitation. In such cases, CL microscopy and spectroscopy are valuable methods in identifying various impurities, defects, and their complexes, and in providing a powerful means for the analysis of their distribution, with spatial resolution on the order of 1 pm and less. ... 

Single-crystal diamond is the ideal material with remarkable optical properties, high heat resistance, extreme hardness, and excellent chemical resistance. But, because of its high cost and size limitation, it is only used in exceptional cases, such as the window... 

The chemical composition and crystal structure of a mineral determine its physical and optical properties. The diamond crystalline lattice structure (Fig. 4.3.2)... 

Fig. 5 Chemical structure (a), absorption (a) and emission (b) spectra of POWT in different buffer solutions pH 2 (open diamond), pH 5 (open square), pH 8 (triangle) and pH 11 (x).(c) The charge of the zwitter-ionic side chain, schematic drawing of proposed backbone conformations and optical properties of POWT at different pH [9]...

There are three types of gemstone materials as defined by the U.S. Federal Trade Commission (1) (/) natural gemstones are found in nature and at most are enhanced (see Gemstones, gemstone treatment) (2) imitation or simulated, fake, faux, etc, material resembles the natural material in appearance only and is frequendy only colored glass or even plastic and (3) synthetic material is the exact duplicate of the natural material, having the same chemical composition, optical properties, etc, as the natural, but made in the laboratory (2,3). Moreover, the word gem cannot be used for synthetic gemstone material. The synthetic equivalent of a natural material may, however, be used as an imitation of another, eg, synthetic cubic zirconia is widely used as a diamond imitation. 

C. E. Nebel, Transport and Defect Properties of Intrinsic and Boron-Doped Diamond MiloS Neslddek, Ken Haenen and Milan VanSSek, Optical Properties of CVD Diamond Rolf Sauer, Luminescence from Optical Defects and Impurities in CVD Diamond... 

Carbon nanomaterials show a broad range of optical properties, ranging from transparent in the visible and infrared range for diamond to highly absorbing carbon... 

Experiments have established that there are four polymorphs in solid iron (a-, y-, S-, and s-phases). Saxena et al (1993) proposed a fifth iron phase (/3-phase) based on changes in thermal emission while laser heating the sample in a diamond-anvil cell. Boehler (1993) also observed similar changes in optical properties of iron in the same P-T range. Subsequent in situ X-ray diffraction measurements in the laser-heated diamond-anvil cell supported the occurrence of this new iron phase, although the structure of this phase is still under debate (Saxena et al, 1996 Yoo et al, 1996 Andrault et al, 1997, 2000 Saxena and Dubrovinsky, 2000). However, this phase was not observed in... 

The Optical Properties of Diamond, Gordon Davies Fracture in Polycrystalline Graphite, J. E. Brocklehurst... 

For a detailed database of optical properties of diamond, the reader can refer to an excellent monograph by Zaitsev [444, 447]. 

Zaitsev, A. (2001) Optical Properties of Diamond (Springer, Berlin). 

Diamond s properties make it the desirable material in thermal, optical, electrical, electronics, and mechanical applications. It has not been exploited to its maximum potential. Future trends are toward applications in medicine, biology, and the nuclear field. These fields already have applications that use diamond but continuous improvements are being made through research. Diamond is a strong candidate as a substitute for materials currently being used in a variety of applications. Although implementation may be deterred by cost factors or technical issues, the development of new deposition techniques may overcome this limitation. Deposition techniques and a higher control of processes surely will help to launch more sophisticated electronic applications that eventually will realize diamond s superior performance over other materials. 

Franta, D. Ohlidal, I. Bursikova, V. Zajickova, L. Optical properties of diamond-like carbon films containing SiOx. Diamond Relat. Mater. 2003, 12, 1532-1538. 

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