Frequency conversion through wave-mixing in rubidium Rydberg states

We examine frequency conversion through Rydberg states in rubidium vapor using four-wave mixing. Excitation is accomplished through the intermediate 6p state using light at 420 nm in combination with a 1024 nm laser to the 30d state. The application of an additional 780 nm laser resonant with the 5p state results in a generated beam at 480 nm. The dependence of this process on laser frequency, intensity, and atomic density is explored. The application of microwaves allows transitions between neighboring Rydberg states, and is promising for microwave to optical frequency conversion via six-wave mixing.