Power neodymium-glass amplifier of a repetitively pulsed laser

A neodymium-glass diode-pumped amplifier with a zigzag laser beam propagation through the active medium was elaborated; the amplifier is intended for operation in a repetitively pulsed laser. An amplifier unit with an aperture of 20 ? 25 mm and a ~40-cm long active medium was put to a test. The energy of pump radiation amounts to 140 J at a wavelength of 806 nm for a pump duration of 550 ?s. The energy parameters of the amplifier were experimentally determined: the small-signal gain per pass ~3.2, the linear gain ~0.031 cm-1 with a nonuniformity of its distribution over the aperture within 15%, the stored energy of 0.16 ? 0.21 J cm-3. The wavefront distortions in the zigzag laser-beam propagation through the active element of the amplifier did not exceed 0.4? (? = 0.63 ?m is the probing radiation wavelength).