Single mode nitrogen pumped dye laser

Abstract

A N 2-laser pumped, tunable dye laser has been operated in a stable single longitudinal cavity mode without the use of etalons, polarized pump sources or intracavity polarising elements. The all-reflective cavity employs a grazing incidence beam expansion grating and a Littrow tuning grating. The time averaged linewidth of 0.02 cm -1 (630 MHz) for 5 × 10 -3 M R6G dye was observed to be the same as the single shot linewidth, with an efficiency of 0.5%. A dye concentration of 10 -2 M R6G increased the single mode linewidth to the value predicted by a single pass model of the cavity and increased the efficiency to 1.5%. A Littrow grating can be used to replace the feedback mirror and enhance the output signal to noise ratio.