摘要
We present a sensitive scheme, for the first time to our knowledge, to observe photo-retraction （PR） ettects in some nonlinear optical crystals, e,g. β-BBO, LBO and BIBO, pumped by an intense ultrashort laser pulse chain. These quite weak effects are ＂amplified＂ by sensitive cw intraeavity loss modulation. Our results show that they are repeatable and are dependent on pumping power and wavelength, and their response time ranges from tens of seconds to several minutes. The recorded dynamical transitions between the self-focusing to the self-defocusing （or vice versa） induced by the PR effect may be critically important for us to give more insight into the stability of some cascade nonlinear frequency conversions, e.g. multi-stage optical parametric amplifiers.
We present a sensitive scheme, for the first time to our knowledge, to observe photo-retraction （PR） ettects in some nonlinear optical crystals, e,g. β-BBO, LBO and BIBO, pumped by an intense ultrashort laser pulse chain. These quite weak effects are ＂amplified＂ by sensitive cw intraeavity loss modulation. Our results show that they are repeatable and are dependent on pumping power and wavelength, and their response time ranges from tens of seconds to several minutes. The recorded dynamical transitions between the self-focusing to the self-defocusing （or vice versa） induced by the PR effect may be critically important for us to give more insight into the stability of some cascade nonlinear frequency conversions, e.g. multi-stage optical parametric amplifiers.
基金
Supported by the Key Project of the Ministry of Education of China （107047）, the National Natural Science Foundation of China under Grant No 60878017, the Scientific Research Foundation （SRF） for the Returned Overseas Chinese Scholars （ROCS）, and the SZU R/D Fund （200902）.
