Optical nonlinearity of wide-bandgap semiconductor and insulator nanoparticles in the visible and near-infrared regions of the spectrum

Experimental results on the interaction of nanosecond optical pulses at the wavelength of 0.53, 0.65, and 1.06 µm with nanoparticles of crystalline materials with a bandgap of 3 to 7 eV are reported. It is shown that the threshold for the nanoparticles to exhibit a nonlinear response can be as low as 0.05 to 0.5 nJ/cm 2 and that the response can manifest itself as limitation of the radiation or as blooming of the medium. A theoretical model is proposed, which associates these effects with single-photon generation of charge carriers from deep impurity levels produced by defects located near the nanoparticle’s surface.