A four-level system driven by two coherent fields is considered, the probe gain at a short wavelength can be achieved due to the quantum interference in the presence of an incoherent pump.

• 摘要提出一个由两个相干场和一个非相干泵浦驱动的四能级模型，讨论了由于量子干步的作用，在短波长范围内获得的探测场增益。