A scheme for enhancing precursor pulse by Doppler effect is proposed in a room-temperature active-Raman-gain medium. Due to abnormal dispersion between two gain peaks, main fields are advanced and constructively interfere with optical precursors, which leads to enhancement of the transient pulse at the rise edge of the input. Moreover, after Doppler averaging, the abnormal dispersion intensifies and the constructive interference between precursors and main fields is much strengthened, which boosts the transient spike. Simulation results demonstrate that the peak intensity of precursors could be enhanced nearly 20 times larger than that of the input.
© 2012 Optical Society of America
Atomic and Molecular Physics
Original Manuscript: May 10, 2012
Revised Manuscript: July 3, 2012
Manuscript Accepted: July 3, 2012
Published: August 6, 2012
Yandong Peng, Yueping Niu, Lida Zhang, Aihong Yang, Lin Jiang, and Shangqing Gong, "Enhanced optical precursors by Doppler effect via active Raman gain process," Opt. Lett. 37, 3333-3335 (2012)