Ultrafast stop band kinetics in a three-dimensional opal-VO_2 photonic crystal controlled by a photoinduced semiconductor-metal phase transition

摘要

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 meV, occurring during the femtosecond laser pulse excitation, a further increase of the shift up to ～60 meV is observed for ～500 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.