Real-time velocity measurement by the use of a speckle-pattern correlation system that incorporates a ferroelectric liquid-crystal spatial light modulator

Speckle correlation method used to measure object's in-plane velocity

We present a measurement of an object's in-plane velocity in one direction by the use of the speckle correlation method. Numerical correlations of speckle patterns recorded periodically during motion of the object under investigation give information used to evaluate the object's in-plane velocity. The proposed optical setup uses a detection plane in the image field and enables one to detect the object's velocity within the interval (10-150) microm x s(-1). Simulation analysis shows a way of controlling the measuring range. The presented theory, simulation analysis, and setup are verified through an experiment of measurement of the velocity profile of an object.

Analysis of electro-optic crystal-based Fabry-Perot etalons for high-speed spatial light modulators

The use of electro-optic (EO) crystal-based Fabry-Perot modulators (FPMs) as high-speed spatial light modulators is proposed. The FPMs operate with an extremely low drive voltage and a high extinction ratio. It is revealed by analysis of both the linear EO effect and the inverse piezoelectric effect of various EO crystals that three kinds of crystal configuration are suitable as FPMs. One of these is applicable to isotropic crystals, point groups 23 and (-)43m, and the others are better suited for uniaxial EO crystals, point groups (-)42m and 3m. Typical EO crystals suitable as FPMs are ferroelectric crystals such as LiNbO3, LiTaO3, and LiIO3 and sillenite compounds such as Bi12SiO20 and Bi12GeO20 as well as compound semiconductors such as GaAs and GaP.

Real-time holographic vibrometry with a ferroelectric liquid-crystal spatial light modulator

A fast ferroelectric liquid-crystal spatial light modulator, originally developed for optical computing, has found a new application in vibrometry. A new scheme of vibration-synchronized double-exposure holographic interferometry is proposed that makes full use of the speed of the ferroelectric liquid-crystal spatial light modulator. Preliminary experiments were performed that demonstrate virtually continuous real-time vibrometric data acquisition.

Performance comparison of ferroelectric liquid-crystal-technology-based coherent optical multichannel correlators

Our purpose is to compare two architectures when implemented with ferroelectric liquid-crystal technology: the conventional VanderLugt and joint transform correlators. The architectures are compared in the single-correlation and multichannel cases. The analysis covers both theoretical aspects and practical considerations regarding implementation. Specifications for a multichannel correlator design, including considerations of both spatial light modulators and architecture configurations, are discussed. Experimental results are presented for both architectures. Finally, the benefit resulting from extension to multichannel operation is discussed in terms of both multiplexing and algorithmic capabilities.