Generation of UV Radiation (250–260 nm) from Intracavity Doubling of a Single-Mode Ring Dye Laser

Abstract

Molecules whose electronic transitions lie in the UV portion of the electromagnetic spectrum far outnumber those in the visible. Consequently, it is of considerable chemical interest to extend tunable coherent sources to shorter wavelengths. Potential applications are numerous, including photochemical, kinetic, analytical, and spectroscopic studies. We report here the construction of an intracavity-doubled cw ring dye laser producing single-mode UV output in the range 250–260 nm with a free-running jitter of about ±50 MHz over a time interval of a few seconds. High resolution spectra of the Hg ³P₁ - ¹S₀ transition at 253.7 nm are presented. Fluorescence excitation of natural mercury in a bulb yields a spectrum in which the resolution of the hyperfine structure is Doppler limited, whereas excitation of an atomic beam allows subDoppler resolution of these features.