Photostimulated nonlinear optical switching materials based on CdBr0·95Cl0.1 nanocrystalline layers

Abstract New types of crystalline materials based on CdBr0·95Cl0.1 nanolayers have been fabricated. Due to the layered structure, it is possible to achieve nanolayers by cleaving layers of CdBr2 single crystals. These layers anisotropy opens a principal opportunity for fabricating thin CdBr0·95Cl0.1 nanocrystals with a thickness up to several nanometers without additional treatment. We have prepared the samples within a 3–30 nm thickness range. The phototreatment has been performed by bicolor coherent Nd: YAG laser with wavelengths 1540 nm/770 nm. The third-harmonic generation (THG) was detected for a fundamental 20 ns Er-glass laser beam at wavelength 1540 nm with a frequency reception of ∼10 Hz. The phototreatment was done for 2–3 min and was controlled by cw He–Ne laser-induced diffraction patterns. The maximal photoinduced changes have been found for the thinnest film possessing thickness about 3 nm. The THG effect at 1540 nm was maximal at ambient temperature. The effect is explained within a framework of the phenomenological consideration. The principal role of the space electron charge density anisotropy is discussed.