Self-pumped phase conjugation in Bi12TiO20 crystal without external cavity

We present an experimental study of the self-pumped phase-conjugate-mirror (SPPCM) recording in a Bi12TiO20 sample due to the partial internal reflect ion of the pump beam from the rear face. SPPCM has been recorded under an e xternal alternating electric field of a square-wave form with response time equal to 170 s at the pump beam intensity of 520mW/cm(2). The mechanism of the SPPCM formation is similar to that of photorefractive double-phase-con jugate mirrors. The most effective SPPCM is recorded at the much larger pum p-beam-incident angle than it could be supposed from the typical angular de pendence of the two-wave-mixing gain factor. Strong dependence of the gain distribution on the pump-beam-propagation angle is observed. It is found th at the response time strongly depends on the preliminary history of the sam ple.