Phase-Coupling-Induced Ultraslow Light Propagation in Solids at Room Temperature

Abstract

We show that the group velocities of light pulses can be decelerated dramatically by the use of a dispersive phase-coupling effect through a wave mixing process. We have observed experimentally such a phase-coupling-induced ultraslow light propagation with a group velocity as low as $0.05\text{ }\text{ }\mathrm{m}/\mathrm{s}$ in a photorefractive ${\mathrm{B}\mathrm{i}}_{12}{\mathrm{S}\mathrm{i}\mathrm{O}}_{20}$ crystal at room temperature. Moreover, the ultraslow light is amplified in the ${\mathrm{B}\mathrm{i}}_{12}{\mathrm{S}\mathrm{i}\mathrm{O}}_{20}$ crystal because of the unidirectional energy transfer from a coupling beam to the ultraslow light. This technique to produce ultraslow light propagation is valid for all nonlinear wave mixing processes with a dispersive phase-coupling effect.