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The absolute longitudinal distance between two points can be deterinined by the corresponding correlation peaks of two light-waves from a broad-band light source. Using this technique, the height of three-dimensional objects can be measured without 2lz: phase ambiguity. We can also detect the absolute position of scattering seeds in sub-surface or bulk materials such as defects, dislocations or impurities of high purity materials. The wavelet analysis is used to determine the correlation peaks. This technique can be applied to measurement of thickness of a few hundred microns.

The use of a broad-band interferometer and its fringe analysis method are presented in which the fractional fringe order method for measuring the absolute thickness. An approximate integer part of the fringe order is estimated by mechanical measurements, and the fractional part is determined by interferometric fringe pattern analysis. The fringe patterns are obtained with a Michelson interferometer by illumination of several selected wavelengths, respectively. The use of the fractional fringe order method can determine accurately more than 2'r phase jumps. The influence of wavelength and approximate integer part offringe order on the measurement accuracy is discussed.

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An optical neural network system using a microchannel plate spatial light modulator (MSLM) and a computer-generated hologram (CGH) displayed on a liquid crystal TV (LCTV) display device are described. In the optical three-layer neural network, the back-propagation learning algorithm is successfully demonstrated with the uniformity of in synaptic connection coefficients in MSLM and the contrast of 20 in neuron output in LCTV, respectively. To make a dynamic optical interconnection and analog optical computing, CGHs are displayed on LCTV. As applications of displaying CGHc, spatial filtering and moving pictures demonstration are performed.