Power‐scaling effects in dye lasers under high‐power laser excitation

Eight laser dyes emitting in the spectral region from 550 to 915 nm were investigated to determine their power scalability under excitation by Q‐switched frequency‐doubled Nd : YAG lasers possessing up to 480 mJ pulse energy at 10 Hz pulse repetition frequency (PRF). Conversion efficiencies for some dyes begin to be limited at pump‐power densities as low as 14 MW/cm2 due to excited‐state absorption of the pumping radiation. The dependence on resonator length of dye spectral emission, conversion efficiency, and temporal modulation are reported. Divergence of the beam emerging from the dye laser was found to be adversely affected by measures taken to avoid output power saturation at high pump‐power densities.