Effect of SGC on transient evolution of GWI in a Doppler broadened quasi Λ-type four-level system

• Published in: Optoelectronics letters Vol. 8; no. 5; pp. 393 - 396
• Main Authors: Liu, Zhong-bo, Tong, Dian-min, Fan, Xi-jun
• Format: Journal Article
• Language: English
• Published: Heidelberg Tianjin University of Technology 01.09.2012
• Subjects: Lasers; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy; SGC; 原子系统; 四能级系统; 多普勒展宽; 无粒子数反转; 演化; 瞬态; 稳定值; Rabi Frequency; Pump Field; Frequency Detunings; Atomic System; Driving Field
• ISSN: 1673-1905; 1993-5013
• DOI: 10.1007/s11801-012-2252-3

In this paper,we study the effect of spontaneously generated coherence（SGC） on transient evolution of gain without inversion（GWI） in a Doppler broadened quasi Λ-type four-level atomic system.It is shown that transient evolution of GWI is very sensitive to the variation of SGC strength,and the transient maximum value and steady value of GWI both increase with SGC strength increasing.The transient and steady values of GWI with SGC are much larger than those without SGC.When Doppler broadening is present,the transient maximum value and steady value of GWI first increase and then decrease with Doppler broadening width（D） increasing,and the value of D which corresponds to the maximum transient GWI is different from that corresponding to the maximum steady GWI.The time needed for reaching the steady GWI increases with D increasing.The steady GWI,which is larger than that without Doppler broadening（D = 0）,can be obtained by choosing appropriate D and SGC strength.