Microinterferometric optical phase tomography for measuring small, asymmetric refractive-index differences in the profiles of optical fibers and fiber devices

A new technique, microinterferometric optical phase tomography, is introduced for use in measuring small, asymmetric refractive-index differences in the profiles of optical fibers and fiber devices. The method combines microscopy-based fringe-field interferometry with parallel projection-based computed tomography to characterize fiber index profiles. The theory relating interference measurements to the projection set required for tomographic reconstruction is given, and discrete numerical simulations are presented for three test index profiles that establish the technique's ability to characterize fiber with small, asymmetric index differences. An experimental measurement configuration and specific interferometry and tomography practices employed in the technique are discussed.     

Chaotic-oscillator measuring devices

Algorithms for diagnosis of the chaotic-oscillator parameter, which is defined as the output signal of a measured-quantity sensor, are considered. The design of measuring devices based on a chaotic oscillator is discussed. Translated from Izmeritel'naya Tekhnika, No. 5, pp. 22–24, May, 2000.     

Metrological provisions for built-in measuring devices

Translated from Izmeritelnaya Tekhnika, No. 6, pp. 59–60, June, 1992.     

Method for measuring veiling glare in high-performance display devices

An experimental method for measuring the veiling glare characteristics of display devices is presented. The measured veiling glare ratio (G) is taken to be the luminance in the surrounding bright field divided by the luminance in a dark circle. The method is based on a collimated conic probe that minimizes signal contamination from bright surroundings allowing for measurements of low luminance in a circular dark spot of a test pattern. A correction factor computed with test patterns having opaque spots is introduced. The factor is expressed as a bivariate function of the dark-spot radius and the distance between the probe and the emissive surface. We studied the uncertainty introduced by the method by measuring veiling glare test patterns printed on radiographic film for which the transmission of the dark spots was determined experimentally. Performance characterization measurements show that signal contamination is less than 10(-4) of the bright field surrounding a dark circle. Our results show that G of a few hundred can be measured with an uncertainty of a few percent, and ratios of approximately 10(3) can be reported within 10%. Finally, we demonstrate the method by measuring G for a high-performance monochrome cathode-ray tube display.     

Electrochromic Materials for optical switching devices

The basic principles of electrochromism have been reported and discussed using the example of WO₃, and some other important electrochromic materials have been described which have a number of interesting technical applications. Both compounds and materials used in ECDs were discussed and the principles of device design were portrayed, using as an example a reflective ASSD. By continuing the search for new electrochromic compounds and by further improving device design and cost optimization the applications of these materials are bound to increase.