Numerical Study on Efficient Optical Switching Based on the Nonlinear Phenomenon in a Guided-Mode Resonant Grating with Kerr Medium

Optical switching in a guided-mode resonant grating (GMRG) with a Kerr medium was numerically simulated by the nonlinear finite differential time domain (FDTD) method. The asymmetric resonant grating was adopted to have two resonant reflection peaks for the pump light and the probe light. When the pump light had a wavelength which was slightly longer than the resonant wavelength, the light was suddenly enhanced at a certain intensity because of the nonlinear resonance phenomenon. This resonance is effective in reducing the pump intensity for optical switching. When we assumed the resonant grating of polydiacetylene toluene sulphonate (PTS) with a linear refractive index of 1.88, a third-order susceptibility of 8.5 × 10⊃−0 esu and Q factors of resonant reflection which were ∼800, the pump light of 15 kW/mm⊃ changed transmittance of the probe light from 0 to 80%. 2005 The Optical Society of Japan