Adopting noise initiation model of stimulated Brillion scattering (SBS), the characteristic of transmitted energy and power in CS2 liquid media under non-focusing pump is investigated numerically. The results show that, the waveform of transmitted pulse with increasing input energy shows the characteristic of power limiting. And the transmitted energy varies linearly with input energy withont the energy limiting effect. When 1053 nm 20 ns Nd:YLF laser was used as pump in a 3∶1 inverse expansion system are using attenuators to adjust input energy in the rang of 2 to 92 mJ, the rules of transmitted energy and waveform versus input energy are acquired, and compared with the results of focusing pump. The experimental results are in good agreement with the theoretical simulations. Because the optical breakdown takes place at high input energy under focusing pump, the power limiting with non-focusing pump is applicable under the circumstances of high power and energy.

Adopting noise initiation mode of stimulated Brillion scattering (SBS), the influence of focal length on optical limiting power and energy is numerically simulated. It shows that the characteristic of limiting power and energy are controlled by focal length. When focal length is moderate, say 15cm, the limiting energy is lowest. When focal length is short, say 5cm, the characteristic of limiting power is close to ideal. In experiment, focusing 8ns, 1064nm, 16mJ pulses into CCl4 medium, the variation of limiting power and energy versus focal length is investigated. The experimental results are in good agreement with the conclusions predicted by the simulations.

No abstract

No abstract