Pulsed tunable dye laser with a low level of wide-band background

A bent resonator with radiation extracted through a rotating mirror was developed for suppressing a wide-band superradiance background (amplified spontaneous emission) in pulsed tunable dye lasers. At the exit from the oscillator the superradiance energy was less than 5×10^–6 of the narrow-band (0.01 nm) output energy. For a two-stage amplifier utilizing an ethanol solution of rhodamine 6G pumped by a pulsed YAG laser with a peak power of 2.8 MW (λ = 532 nm), the maximum laser efficiency was 20% and the superradiance background over the whole tuning range (560–620 nm) was less than 10^–3 of the output energy.