Graded-gain dye laser amplifiers: an experimental investigation

The influence of inhomogeneous distributions of gain and refractive index produced by the pumping radiation on the performance of dye-laser amplifiers is discussed. Experimental measurements in capillary cylindrical cells and planar cells are reported for single-pass, double-pass, and ring configurations. Gain factors up to 85,000 have been obtained at low signal input with rhodamine 6G in ethanol. A saturated gain of 5000 at 100-mJ output with an over-all efficiency of 0.1 per cent has been achieved without full optimization of the amplifier parameters. The reported results indicate that a two-stage double-pass amplifier driven by a dye-laser oscillator in the milliwatt region can be used as an efficient high-energy light source.