Observation of a Hole in the Laser-Induced Cesium Beam Spectrum

We experimentally observed a depression in the laser-induced cesium beam fluorescence spectrum. This paper describes the optical configuration we realized and proves that the hole can be used for laser frequency stabilization. The spectrum was recorded under different conditions. We theoretically analyzed the physical origin of this effect and found that the hole could have a sub-natural line width. This indicates that it could have great application prospects in atomic experiments and beam-type quantum precision instruments due to the simple construction.