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 (λ=1.06 μm; W=30 MW; pulse duration within the 30–50 ps) was used as a source of pumping light and the nitrogen laser (λ=337 nm) has been applied as a source of the photoinducing light. With increasing intensity of the photoinducing beam, the SHG (λ=0.53 μm) signal increased and achieved a maximum (χ₂₂₂=10.1 ± 0.13 pm/V) at a photon flux of about 1.61 GW/cm². 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.