SiC nanocrystals embedded in oligoetheracrylate photopolymer matrices; new promising nonlinear optical materials

Photoinduced optical phenomena in SiC nanocrystallites embedded within the photo-polymer oligoetheracrylate matrices have been studied using experimental nonlinear optics, particularly photoinduced optical second harmonic generation (SHG). The YAG-Nd-laser (lambda = 1.06 mu m; W= 30 MW, pulse duration within the 30-50 ps) was used as a source of pumping light and the nitrogen laser (lambda, = 337 nm) has been applied as a source of the photoinducing light. With increasing intensity of the photoinducing beam, the SHG (lambda = 0.53 mu m) signal increased and achieved a maximum (chi(222) = 10.1 +/- 0.13 pm/V) at a photon flux of about 1.61 GW/cm(2). With decreasing temperature, the SHG signal strongly increases within the temperature range 25-30 K. Time-dependent probe-pump measurements indicate an existence of the SHG maximum for a pump-probe time delay of about 20 ps. The SiC hexagonal structural components play a key role in the observed photoinduced nonlinear optical effects. Large values of the nonlinear optical constants as well the good technological parameters open a possibility to enhance the nonlinear optical susceptibilities. (C) 2000 Elsevier Science B.V.. All rights reserved.