Photoinduced non-linear optical diagnostic of InI ferroelastic nanocrystals

Photoinduced second harmonic generation was established in the centrosymmetric layered crystals of InI. The effect was grounded on occurrence of photoinduced optical second harmonic generation in the ferroelastic phase of the InI crystals. As a subject of investigations layered ferroelastic crystal of InI was chosen. It was found that the ferroelastic phase disappears during decrease of the nanolayers from 15 nm up to 6 nm. Such effects are explained by occurrence of anharmonic phonon modes confined by the walls of the layered crystals. We have found that the effect may be of importance for the further investigations of the layered nanocrystals. At the same time the giant value of the photoinduced SHG indicates on a possible using the nanolayered crystals like promising non-linear optical crystals.