Abstract
Novel materials for the infrared two-photon absorption - Tl1-xIn1-xSnxSe2 single crystals (x=0.1,0.2) were grown. Two-photon absorption (TPA) was studied at CO2 laser wave-length 9.4 mu m with pulse duration 1 mu s. The studies were performed at different temperatures and for the nanocrystallite sizes varying within the 7-200 nm. The studies have shown that the TPA may be enhanced during the decrease of the nanocrystallite sizes below 50-60 nm. There exists also some critical x value at which the TPA value begin substantially to increase. The studied nanocrystallites are relatively stable to the infrared laser treatment and are not hygroscopic which allow to use them in different IR optoelectronic devices.