Tl_4SnS_3, Tl_4SnSe_3 and Tl_4SnTe_3 crystals as novel IR induced optoelectronic materials

摘要

A new type of chalcogenide crystals Tl_4SnS_3, Tl_4SnSe_3, Tl_4SnTe_3 easily processing by external IR laser light is fabricated. For the titled crystals linear electroop-tical effect was induced by external IR polarized light formed by two coherent beams of Englass nanosecond laser at fundamental wavelength 1540 nm. The detection of the electrooptical coefficient was performed by continuous-wave 1 W CO_2 laser at probing wavelength 10.6 urn. The origin of the effect is caused by an occurrence of the thin (up to 50 nm) photoexcited nanosheets which forms near the surface space charge density non-centrosymmetry. The relaxation of the electrooptics after switching off of the photoinduced Englass laser beam is explored for different types of samples at different power densities. The crystals may be used for IR optical triggering.