Analysis of the performance of a thermal defocusing optical limiterin the transient regime

摘要

A theoretical analysis of the performance of a thermal defocusingnoptical limiter in the transient regime-i.e., when the laser pulsenduration is comparable to the acoustic transit time which governs thenlimiter response-is presented. First, an expression is obtained for thentime- and space-dependent refractive index changes induced by a lasernpulse in an absorbing liquid. This is used to calculate the nonlinearnphase change experienced by the laser pulse while traversing thenabsorbing medium and then the transmission of the optical limiter.nResults on the dependence of the optical limiter's performance on lasernpulse duration are presented in a general form and also by considering anspecific example