INJECTION-SEEDED DIODE-PUMPED REGENERATIVE RING ND-YAG AMPLIFIER FOR SPACEBORNE LASER RANGING

We report on a small, all solid state, regenerative ring amplifier designed as a prototype for space application. Features include dual side pumping of a 2 mm x 2 mm x 10 mm Nd: YAG slab and a triangular ring cavity design, which minimizes the number of optical components. The pump head was fitted with twin single-bar diode arrays consisting of 960 individual stripes, temperature tuned to the Nd: YAG pump bands at 809 nm and capable of operation up to 100 Hz. The single-pass gain of this head was measured at 13% for a pump pulse energy of 18.4 mJ from the diode arrays and the cavity round trip transit time was 3.1 ns. The ring has amplified 170 ps pulses with 10(-13)-10(-14) j of energy by a factor of more than about 10(6) while preserving both the temporal and spatial shape of the pulses. The seeding threshold was about 10(-15) J and a maximum saturated output energy of about 40 muJ was obtained when seeded with pulses greater than 1 pJ. Comparison with modelled performance is also given.