Optically stimulated IR non-linear optical effects in the Tl3PbCl5 nanocrystallites

•Non-linear optical properties in the Tl3PbCl5 nanocrystallites were found.•The role of the sizes play crucial role.•The effect is casued by contributions of electron as well as phonon subsystem.

We have shown that use of the Tl3PbCl5 nanocrystallites leads to the occurrence of a substantial increase of the SHG induced by the coherent doubled frequency light. We have found that for the fundamental microsecond 10.6 μm wavelengths, there exists a possibility to increase the SHG during illumination at 5.3 μm wavelength. The detailed analysis of the IR induced SHG has shown that the nanocrysatalline interfaces play here the principal role. Another important factor is the contribution of the phonon subsystem due to the presence of the IR stimulated anharmonic phonons. These results are compared with those of bulk crystals.