Optical information storage using refresh via phase conjugation

Abstract In this paper we discuss the possibility for realizing an optical memory using dynamic refreshment. Via phase-correct back-coupling by means of nonlinear optical phase conjugation the information stored in a photorefractive crystal is incessantly read out, transmitted into an auxiliary memory and from this back into the crystal again and in this way refreshed. Practical realizations and first results are presented

Stationary and transient interferometry with a self-pumped phase conjugate mirror

For the application of self-pumped phase-conjugate mirrors in interferometric arrangements, the properties of such devices have to be characterized. In this paper, we define figures of merit on the basis of experimental investigations and show, how the field of possible interferometric applications is limited in the case of a non-ideal phase conjugation process under stationary and transient conditions

Optical measurements with phase-conjugate mirrors

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