Two-Photon Resonant Parametric and Wave-Mixing Processes in Atomic Sodium

Abstract

The generation of coherent radiation in the UV and VUV region through four wave mixing processes has been the subject of several recent reports. In the first, the Na 4d D_J level is populated by two-photon excitation and a cascade of IR stimulated emission ensues. Photons from these cascades of frequency ω_IR can then mix with two laser photons with total energy related to 2ω_L, yielding UV photons at a frequency ω_UV = ω_IR + 2ω_L. Using various members of the cascade, HARTWIG [1] generated radiation at 330 nm and 333nm, while Wu and Chen [2] have produced radiation at 383 nm and 388nm using this procedure.