Effect of reflection and 2K gratings on self-pumped phase-conjugate mirrors: theoretical and experimental studies

The effect of reflection and 2K gratings on the efficiency of photorefracti ve self-pumped phase-conjugate mirrors (SPPCMs) was studied theoretically a nd experimentally. Semilinear SPPCM's of BaTiO3 are used as an example. It is shown with numerical calculations that in normal experimental configurat ions all these gratings are helpful for the performance of the SPPCM's. Wit h a 45 degrees-cut BaTiO3:Ce we determined-experimentally the variation of reflectivity of a semilinear SPPCM when the crystal's gain coefficients tha t correspond to the gratings were changed by variation of the cavity length of the semiresonator in the SPPCM. The experimental results verified the t heoretical predications. The validity of our conclusions for SPPCM's with o ther photorefractive crystals such as KTaxNb1-xO3 and (KyNa1-y)(2Z)(SrxBa1- x)(1-Z)Nb2O6 is discussed. (C) 1999 Optical Society of America [S0740-3224( 99)02102-5]. OCIS codes: 060.4370, 160.5320, 190.5040.