Nonlinear optical tuning of a two-dimensional silicon photonic crystal

Abstract

We use the real (Kerr) and imaginary (two photon absorption) parts of a third order optical nonlinearity to tune the long $(1.6\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m})$ and short wavelength $(1.3\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m})$ band edges of a stop gap in a two-dimensional silicon photonic crystal. From pump-probe reflectivity experiments using $130\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$ pulses, we observe that a $2\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$ pulse induces optical tuning of the $1.3\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$ edge via the Kerr effect whereas a $1.76\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$ pulse induces tuning of the $1.6\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$ band edge via both Kerr and Drude effects with the latter related to two-photon induced generation of free carriers with a lifetime of $\ensuremath{\sim}900\phantom{\rule{0.3em}{0ex}}\mathrm{ps}$.