Simultaneous strong coherent pumping of the two transitions of a V-level atom with very different decay rates has been predicted to create almost perfect inversion on the narrower transition. Using the example of the blue and red transitions in Strontium we show that for suitable operating conditions the corresponding resonant gain can be used to continuously operate a laser on the narrow transition. In particular, for a strong detuning of the pump field with respect to the narrow transition, coherent laser emission occurs close to the bare atomic transition frequency exhibiting only a negligible contribution from coherent pump light scattered into the lasing mode. Calculations of the cavity output spectrum show that the resulting laser linewidth can get much smaller than the bandwidth of the pump light and even the natural linewidth of the narrow atomic transition. Its frequency is closely tied to the atomic transition frequency for properly chosen atom numbers. Simulations including atomic motion show Doppler cooling on the strong transition with minor motion heating on the lasing transition, so that continuous laser operation in the presence of a magneto-optical trap should be possible with current experimental technology.

据预测，衰减程度非常不同的V级原子的两个跃迁同时强相干泵浦会在较窄的跃迁上产生几乎完美的反转。以锶中的蓝色和红色跃迁为例，我们表明，对于合适的工作条件，可以使用相应的谐振增益在狭窄的跃迁上连续操作激光器。特别是，对于泵浦场相对于窄跃迁的强烈失谐，相干激光发射在接近裸原子跃迁频率的位置发生，仅表现为来自散射到激光模式的相干泵浦光的贡献很小。腔输出光谱的计算表明，所得的激光线宽可以变得比泵浦光的带宽小得多，甚至比窄原子跃迁的自然线宽还要小。对于正确选择的原子序数，其频率与原子跃迁频率紧密相关。包括原子运动在内的模拟表明，在强跃迁上进行多普勒冷却，而在激射跃迁上进行轻微运动加热，因此在当前的实验技术下，在有磁光阱的情况下连续激光操作应该是可能的。