New 3D multipass amplifier based on Nd:YAG or Nd:YVO4 crystals

We report on new simple and efficient multipass amplifiers using prisms or corner cubes to perform several passes in different planes of incidence. This scheme provides an optimized overlap between the signal passes and the pumped volume. We investigated our amplification geometry with Nd:YAG and Nd: YVO4 crystals : the use of a low doped (0.3%) Nd:YVO4 crystal allowed better thermal behaviour and higher performances. We amplified a pulsed microlaser (110 mW of average power at 1064 nm) and obtained a diffraction-limited output beam with an average power of 5.7 W for 15 W of pump power and a small-signal gain of 56 dB in a 6-pass configuration.