We have operated a single longitudinal mode of a solid-state dye laser osci
llator in a Littman configuration. The host material of the solid-state gai
n medium was rhodamine dye-doped poly (methyl methacrylate). The pumping so
urce was the second harmonic of a Nd:YAG laser with a repetition rate of 10
Hz. The measured linewidth of the laser output was about 1.5 GHz.