Experimental investigation of the slow light and superluminal effects in high-quality three-dimensional colloidal photonic crystals

Abstract

We investigated by time-of-flight technique the slow light and superluminal effects in high-quality three-dimensional （3D） colloidal photonic crystals （PCs） with opal structure, fabricated by pressure controlled isothermal vertical deposition technique. They produce high transmission in the pass bands and sharp band edges due to low volume density of defects and dislocations. The variation of the group velocity across the short-wavelength band edge was measured. Group velocity as low as 0.43c was observed near the band edge while group velocity as high as 1.34c was found in the band gap. We have also simulated the transportation of ultrashort pulses through 3D PCs and compared the simulation results with the experimental ones.