The probe gain with and without inversion in a four-level atomic model: light amplification at a short wavelength

• 来源期刊: 中国物理（英文版）
• 学科: 物理学
• 关键词: probe gain with or without inversion atomic coherence Raman scattering gain
• 年，卷（期）: 2003,（1）
• 页码范围: 39-44
• 页数: 6页
• 分类号: O4
• 语种: 英文

摘要

We propose a new four-level atomic model for achieving light amplification at a short wavelength, where direct incoherent pumping into the top level is avoided by the advantage of coherent pumping. In this model, the lower level of the probe transition is an excited state but not the usual ground state. By analytical as well as numerical calculations, we find that the probe gain, either with or without population inversion, which depends on the relation between spontaneous decay rates γ42 and γ21, can be achieved with proper parameters. We note that the Raman scattering gain always plays an important role in achieving the probe amplification.