Infrared optics

Infrared optics is a fast growing area in which CVD plays a maj or role, particularly in the manufacture of optical IR windows. 1 The earths atmosphere absorbs much of the infrared radiation but possesses three important bandpasses (wavelengths where the transmission is high) at 1-3 im, 3-5 im and 8-17 pm. As shown in Table 16.2, only three materials can transmit in all these three bandpasses single crystal diamond, germanium, and zinc selenide. 

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 most common IR window materials are zinc sulfide, which is translucent, and zinc selenide, which is transparent. Both of these materials are made by low-pressure CVD by the reaction of vaporized zinc and hydrogen sulfide or selenide (see Ch. 12). Germanium, another common IR window material, is also produced by CVD (see Ch. 8). 

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False documents and securities detection Ultrasonic, infrared, optical. X-ray instruments... 

AH intrinsic germanium metal sold is specified to be N-type with a resistivity of at least 40 H-cm at 25°C or 50 H-cm at 20°C. Germanium metal prepared for use in infrared optics is usuaHy specified to be N-type with a resistivity of 4-40 Hem, to be stress-free and fine annealed, and to have certain minimum transmission (or maximum absorption) characteristics in the 3—5 or 8—12 pm wavelength ranges. Either polycrystaHine or single-crystal material is specified. 

Laser Photochemistry. Photochemical appHcations of lasers generally employ tunable lasers which can be tuned to a specific absorption resonance of an atom or molecule (see Photochemical technology). Examples include the tunable dye laser in the ultraviolet, visible, and near-infrared portions of the spectmm the titanium-doped sapphire, Tfsapphire, laser in the visible and near infrared optical parametric oscillators in the visible and infrared and Line-tunable carbon dioxide lasers, which can be tuned with a wavelength-selective element to any of a large number of closely spaced lines in the infrared near 10 ]lni. 

Monitor exterior wall temperature with infrared optical detection system, and operating instructions for operator response if high temperature signal occurs... 

Boronic acid-containing polyaniline has also been utilized in diabetes-related research. One such polymer (23) (Fig. 17) has been observed to exhibit a linear near-infrared optical response to saccharides.43 The polymer was prepared by the copolymerization of aniline with 3-aminophenylboronic acid using lOmM (NH4)S208 in 1M HC1. The films were observed to undergo changes in the absorption spectra on addition of saccharides at pH 7.2. 

Walsh J.E., MacCraith B.D., Meany M., Vos J.G., Regan F., Lancia A., Artjushenko S., Sensing of chlorinated hydrocarbons and pesticides in water using polymer coated mid-infrared optical fibres, Analyst, 1996 121 789-792. 

Lundgren et al. [132] showed that the cadmium signal could be separated from a 2% sodium chloride signal by atomising at 820 °C, below the temperature at which the sodium chloride was vaporised. This technique has been called selective volatilisation. They detected 0.03 xg/l cadmium in the 2% sodium chloride solution. They used an infrared optical temperature monitor to set the atomisation temperature accurately. 

Alternatively non-contacting measurement systems may be considered for distinguishing between the different textile families, e.g. based on analyses of the optical or infrared optical spectra of the textiles. However, difficulties will arise, considering the variety of textiles in use. 

Detectors with complete black body rejection capability are usually less sensitive to fires than a single frequency infrared optical detector. Because it s discrimination of fire and non-fire sources depend upon an analysis of the ratio between fire and reference frequencies, there is a variation in the amount of black body rejection achieved. A detector s degree of black body radiation rejection is in inversely proportion to its ability to sense a fire. The detectors are limited to applications that involve hydrocarbon materials. 

Handbook of Infrared Optical Materials, edited by Paul Klocek... 

M. A. Franceschini and D. A. Boas. Noninvasive measurement of neuronal activity with near-infrared optical imaging. Neuroimage, 21 372-386, 2004. 

Y. Hoshi. Functional near-infrared optical imaging Utility and limitations in human brain mapping. Psychophysiology, 40 511-520, 2003. 

R. Kennan, D. Kim, A. Maki, H. Koizumi, and R. T. Constable. Non-invasive assessment of language lateralization by transcranial near infrared optical topography and functional mri. Human Brain Mapping, 16 183-189, 2002. 

G. Taga, K. Asakawa, A. Maki, Y. Konishi, and H. Koizumi. Brain imaging in awake infants by near-infrared optical topography. PNAS, 100(19) 10722-10727, 2003. 

In addition to a review of the recent developments in the preparation of chiral amino compounds, developments concerning the interpretation of their ORD and CD in the visible and ultraviolet spectral regions will be reviewed, together with the emerging impact of vibrational (infrared) optical activity (VOA) observations, including vibrational circular dichroism (VCD) and Raman optical activity (ROA) measurements23, on important stereochemical problems concerning chiral amino compounds. 

Enomoto, Y., Murakami, T. and Suzuki, M., Infrared Optical Detector Using Superconducting Oxide Thin Film. Physica C 153-155 1592(1988). 

Volz, F. E., Infrared Optical Constants of Ammonium Sulfate, Sahara Dust, Volcanic Pumice, and Flyash, Appl. Opt., 12, 564-568 (1973). 

Fig. 3 Infrared optical transmission and reflection spectra of the samples shown in Fig. 2 the spectrally matching transmission dips and reflection peaks represent photonic stopgaps. Upper and lower plots correspond to upper and lower rows in Fig. 2...

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