Directional coherent light via intensity-induced sideband emission.

ABSTRACT: We introduce a unique technique for generating directional coherent emissions that could be utilized to create coherent sources in a wide range of frequencies from the extreme ultraviolet (XUV) to the deep infrared. This is accomplished without population inversion by pumping a two-level system with a far-detuned strong optical field that induces the splitting of the two-level system. A nonlinear process of four-wave mixing then occurs across the split system, driving coherent emission at sidebands both red- and blue-detuned from the pump frequency, and propagates both forward and backward along the pump beam path. We observed this phenomenon in dense rubidium vapor along both the D₁ and D₂ transitions. The sideband emission exhibits a short pulse duration (<1?ns) with threshold-like behavior dependent on both the pump intensity and Rb vapor density. This technique offers a new capability for manipulating the emission frequency simply through intensity-induced atomic modulation that can be scaled to most frequency regimes using various atomic/molecular ensembles and pump energies.

SUBMITTER: Traverso AJ 

PROVIDER: S-EPMC6062192 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature