Optical measurements with phase-conjugate mirrors

Phase-conjugate mirrors on the basis of photorefractive crystals offer inte resting possibilities of application for optical measurement systems. In th is paper we report on the application of phase-conjugate mirrors (PCMs) for optical measurement techniques. We show different schemes for realizing PC Ms and discuss characteristics such as reflectivity, fidelity, and time beh avior. We demonstrate that two-beam interferometers with PCMs and with a suitable phase-shifting unit in the reference arm have general advantages compared w ith conventional systems. It is shown that self-pumped PCMs (SPPCMs) could also be successfully used for novelty filtering systems comparing a present state of a signal phase with a reference phase. It is found that SPPCMs ca n improve both the axial and the lateral resolution of a confocal microscop e. A 30% better resolution of the PCM system is established.