IR operation by third harmonic generation of Tl_4PbTe_3 and Tl_4SnS_3 single crystals

摘要

We have discovered substantial influence of the 3 μs CO_2 laser treatment on the output third harmonic generation (THG) for Tl_4SnS_3 and Tl_4PbTe_3 single crystals. The treatment was performed in the regime of the pump-probing delay. The optimal pump-probe delaying time was 230 ps for the Tl_4SnS_3 crystals and 250 ps for the Tl_4PbTe_3 single crystals. It is crucial that for the Tl_4PbTe_3 the effect is substantially smaller. The effect may be explained within a framework of conception of excitation of the effective pho-non subsystem effectively contributing to the THG.