The spectral radiance between 0.42 μ. and 1.1 μ of rubidium and cesium vapor arc lamps was measured for various input powers and vapor pressures. A strong resonance broadening of the resonance lines was observed at high pressures. A strong continuum in the visible is tentatively attributed to Stark broadening of the overlapping lines of the higher order numbers of the 6p-nd and 5d-nf series and to the related series border continua. Data are given for total radiance (0.42–1.1 μ) as function of pressure, for the efficiency vs power input, and the lamp voltage and current.
D. Fromm, "Spectral Radiance Between 0.42 μ and 1.1 μ of Rubidium and Cesium Vapor Arc Lamps as Function of Power Input and Pressure," Appl. Opt. 9, 913-923 (1970)