: Kowarschik, R.; Wenke, L.; Baade, T.; Esselbach, M.; Kiessling, A.; Notni, G.; Uhlendorf, K.

Abstract
Phase-conjugate mirrors on the basis of photorefractive crystals offer interesting possibilities of application for optical measurement systems. In this paper we report on the application of phase-conjugate mirrors (PCMs) for optical measurement techniques. We show different schemes for realizing PCNIs and discuss characteristics such as reflectivity, fidelity, and time behavior. We demonstrate that two-beam interferometers with PCNIs and with a suitable phase-shifting unit in the reference arm have general advantages compared with conventional systems. It is shown that self-pumped PCNIs (SPPCNIs) 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 SPPCNIs can improve both the axial and the lateral resolution of a confocal microscope. A 30% better resolution of the PCM system is established. We demonstrate that two-beam interferometers with PCNIs and with a suitable phase-shifting unit in the reference arm have general advantages compared with conventional systems. It is shown that self-pumped PCNIs (SPPCNIs) 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 SPPCNIs can improve both the axial and the lateral resolution of a confocal microscope. A 30% better resolution of the PCM system is established.