Ultrafast Bragg switching induced by a phase transition in a 3D photonic crystal

Abstract

We demonstrate ultrafast shifting of a photonic stop band driven by a photoinduced phase transition in vanadium dioxide (VO 2 ) forming a three-dimensional photonic crystal. An ultrashort 120-fs laser pulse induces a phase transition in VO 2 filling the pores of an artificial silica opal, thus changing the effective dielectric constant of the opal. Consequently, the spectral position of the photonic stop band blue-shifts producing large changes in the reflectivity. The observed switching of the photonic crystal is faster that 350 fs. The demonstrated properties of opal-VO 2 composite are relevant for potential applications in all-optical switches, optical memories, low-threshold lasers, and optical computers.

Ultrafast tuning of two-dimensional planar photonic-crystal waveguides via free-carrier injection and the optical Kerr effect

“…A number of different proposals and experimental demonstrations have emerged over the past decade. The most promising mechanism for ultrafast tuning involves optically inducing of changes in the refractive index of one or both of the constituents of a photonic crystal via free-carrier injection, [1][2][3][4][5] the optical Kerr effect, 3,5,6,7 or the optical Stark effect. 8 In this paper comprehensive femtosecond pump-probe second-harmonic (SH) and reflectivity experiments are employed to characterize the roles of free carriers and the optical Kerr effect in tuning leaky eigenmodes of a GaAs planar photoniccrystal waveguide (PPCW).…”