Self‐reading geometry conjugators with copper‐doped photorefractive (K<sub>0.5</sub>Na<sub>0.5</sub>)<sub>0.2</sub>(Sr<sub>0.75</sub>Ba<sub>0.25 </sub>)<sub>0.9</sub>Nb<sub>2</sub>O<sub>6</sub> crystals and their applications

Abstract

The dependence of the reflectivity on the distance of the spots corresponding to the two incident beams on crystals is measured and analyzed in self-reading geometry conjugators (SRGCS) with Cu-doped single-domain photorefractive (K0.5Na0.5)0.2(Sr0.75Ba0.25)0.9Nb2O6 CrYStals. Double peaks in some dependence are observed and used to investigate the mechanism of SRGCS. The dynamic features of the two phase-conjugate beams and the decrease of the specular reflectivity of the probing beam in SRGCS are observed and analyzed. A bump in the probing beam’s phase-conjugate replica as a result of a short pause of the incident pumping beam is analyzed in terms of the pyroelectric effect and photovoltaic effect. A comparison of results on conjugation fidelity, response rate, and threshold between CAT self-pumped phase conjugators and SRGCS is given. Real-time vertical and horizontal high-pass filtering, real-time double-exposure interferometry, and detection of the blemishes caused by amplitude defects in optical systems are demonstrated experimentally. The corresponding theoretical analyses are also given.