Significant propagation reduction of an optical pulse in an active Raman gain scheme

摘要

We report an experimental investigation of significant optical-pulse propagation reduction using a three-state active Raman gain scheme. This scheme which varies fundamentally from the common electromagnetically induced transparency scheme, is capable of achieving ultraslow and distortion-free propagation of a pulsed probe field. The group velocity behavior of this new scheme is drastically different from the conventional electromagnetically induced transparency scheme, and can be used to accurately and directly measure the decoherence rate of a long-lived state. Furthermore, the Raman gain scheme can be broadly tuned, which may has advantages in actual applications.