Amplification mechanism and effects of spontaneously generated coherence on the probe gain in a four-level system

• 来源期刊: 中国物理(英文版)
• 关键词: quantum-jump spontaneously generated coherence
• 年，卷（期）: 2004,（5）
• 页码范围: 692-699
• 页数: 8页
• 语种: 英文

摘要

We investigate the amplification mechanism in a four-level system by both the density-matrix and quantum-jump approaches. We show that the asymmetry between three-photon stimulated emission and one-photon absorption process is responsible for the inversionless amplification of the probe field. We also investigate the effects of spontaneously generated coherence (SGC) on the probe gain, and find that due to the SGC, the probe gain can be greatly enhanced and can be modulated by changing the relative phase between the applied fields.