Power and energy limiting of nanosecond laser pulses by thin stimulated Brillouin scattering cell

Theoretical simulation and experimental studies of optical limiting characteristics in thin stimulated Brillouin scattering (SBS) cell of CCl ₄ have been given. Temporal coupling equations of stimulated Brillouin scattering initiated by thermally excited acoustic wave's field-uniformity existing in thin SBS cell are used. In order to reveal optical limiting performance, several limiting parameters are discussed. The dependences of SBS limiting parameters on pump energy and length of thin SBS cell are studied numerically firstly. The results showed that non-focusing thin SBS cell can limit energy as high as several Joule magnitudes. Power and output energy limiting behaviors have been studied experimentally in our experimental regime. For 1cm thin cell, when laser pulses transmit through the SBS medium CCl ₄; the output power and energy are limited faintly: the output peak power is limited and pulse narrowed without evident power limiting in the following edge; as for 2cm and 4cm cell, both show evident power limiting "step" and energy limiting characteristics, when pump energy increases from 5mJ to 100mJ, the output energy is limited under 20mJ for 2cm SBS cell and 12mJ for 4cm SBS cell, which are quite agree with theoretical calculations in low input energy level.