Theory of Deep Ultraviolet Generation at Maximum Coherence Assisted by Stark-chirped Two-photon Resonance

A scheme is analyzed for efficient generation of vacuum ultraviolet radiation through four-wave mixing processes assisted by the technique of Stark-chirped rapid adiabatic passage. These opportunities are associated with pulse excitation of laddertype short-wavelength two-photon atomic or molecular transitions so that relaxation processes can be neglected. In this three-laser technique, a delayed-pulse of strong off-resonant infrared radiation sweeps the laser-induced Stark-shift of a two-photon transition in a such way that facilitates robust maximum two-photon coherence induced by the first ultraviolet laser. A judiciously delayed third pulse scatters at this coherence and generates short-wavelength radiation. A theoretical analysis of these problems based on the density matrix is performed. A numerical model is developed to carry out simulations of a typical experiment. The results illustrate a behavior of populations, coherence and generated radiation along the medium as well as opportunities of efficient generation of deep (vacuum) ultraviolet radiation.