Ultrafast stop band kinetics in a three-dimensional opal-VO2photonic crystal controlled by a photoinduced semiconductor-metal phase transition

Abstract

The temporal evolution of the photonic stop band shift governed by the photoinduced phase transition in a three-dimensional photonic crystal based on opal-vanadium dioxide has been studied. After the ultrafast shift of the Bragg reflectivity peak by $25\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$, occurring during the femtosecond laser pulse excitation, a further increase of the shift up to $\ensuremath{\sim}60\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$ is observed for $\ensuremath{\sim}500\phantom{\rule{0.3em}{0ex}}\mathrm{ps}$. The theoretical analysis shows that the phase transition during the laser pulse occurs in a limited fraction of opal pores filled with vanadium dioxide, while the later temporal component reflects the spatial evolution of the phase boundary inside each pore.