Abstract

The generation of 145.6-nm radiation by stimulated anti-Stokes Raman scattering in inverted atomic selenium was first reported by Ludewigt et al.¹ We have performed experimental studies of this process in similar excitation conditions, which allow us to compare some of the results in the two studies. The inverted population of the selenium (4p⁴)¹S₀ metastable state relative to the (4p⁴)³P₀ state was prepared by photodissociation of COSe vapor using broadband 193-nm radiation from an ArF excimer laser. The pump beam at 205.1 nm was generated by the first-order Stokes shift in deuterium of narrowband (0.27-cm^–1), 193-nm radiation from a separate, tunable ArF laser. The pump beam was tuned near the selenium (4p⁴)¹S₀–(4p³5s)³P₁ intermediate resonance to generate tunable, coherent radiation at 145.6 nm. We have studied the process in a variety of experimental conditions. Factors affecting the conversion efficiency and tunability include the initial COSe pressure, the intensities and relative timing of the photolyzing and pump beams, and the presence of buffer gases. The experimental results are compared with theoretical calculations based on a recently developed three-level model² which incorporates Doppler broadening and arbitrary decay times.

© 1989 Optical Society of America