Diode-pumped Nd:LNA as a pulsed amplifier

We describe the performances we obtained in a variety of high power diode pumped Nd3+:LNA heads. Two pumping structures are analyzed, which were designed for cylindrical and square cross section rods. The cylindrical rods are tested with 1 joule pumping energy during 200 microsecond(s) . They provide high regenerative gains, in the range 107 to 108 at 20 mJ output energy, with less than 20 passes. The gain transverse distribution looks like a nonuniform cross distribution, at the opposite of that obtained with the square head. The central volume in the rod, whose diameter typically equals 2 mm, only participates to amplification. The purpose of the square structure is both to solve this problem and to optimize the temperature behavior at 10 Hz. Preliminary results are given. In a last step, we also present some spatio-temporal computations in order to understand the growth of the amplified beam as a function of the number of passes in the rod.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.