Tunable four-pass narrow spectral bandwidth amplifier for use at approximately 508 nm.

We report the implementation of a tunable, narrow-spectral-bandwidth, pulsed, four-pass dye-laser amplifier with strongly reduced amplified spontaneous emission. We present temporal pulse profiles, pulse spectra, and gain measurements of the amplifier output for the case of Coumarin 307 dye as the gain medium, seeded at wavelengths of approximately 508 nm and pumped at 355 nm.