Results are presented for generation of 1064 nm and 1573 nm outputs using a common ring resonator for a laser diodeside-pumped zig-zag geometry Nd:YAG laser slab and three NCPM (non-critically phase-matched) KTP crystals. The performance of the resonator at each wavelength is reported, for various configurations. First a common resonator was tested, then a separate resonator was used to gain an understanding of the performance variation with resonator length and OPO output coupling. A second common resonator was then tested, which had an optimized configuration to improve its efficiency. The conversion efficiency of the final design was 35% with 29 mJ output at 1573 nm wavelength for 83 mJ at 1064 nm.
Results are presented for generation of visible and mid-IR output using a common fibre-based laser pump source. This
source comprised a master oscillator power amplifier (MOPA) configuration incorporating a semiconductor seed source.
Operation in the nanosecond and picosecond range is possible via use of the appropriate seed source. The MOPA is
capable of generating 100 W average power in an output beam with an M2 of 1.1. Here the MOPA was operated in the
nanosecond regime, using 100 ns seed pulses at a pulse repetition frequency of 100 kHz. 40 W each of pump power was
available for a frequency doubling and an OPO stage. 9.8 W of green light was generated in an output beam with an M2
of 1.2; using a degenerate PPLN OPO 12.7 W of broadband mid-IR output, with a FWHM linewidth in excess of 170
nm, was generated.
Deformable bimorph mirrors with high damage threshold dielectric coatings are demonstrated as both intra- and extracavity
components with a pulsed energy diode-pumped Nd:YAG zigzag slab laser operating at the 150 mJ level. Two
resonator configurations were tested for intra-cavity operation; with a plane-plane resonator the far-field brightness was
enhanced by up to a factor of 1.5, whilst with a cross-Porro resonator an enhancement of up to 2.2 was achieved. As an
extracavity component far-field beam steering of ±2 mrad was demonstrated.
A laser diode end-pumped Q-switched Nd:YVO4 laser operating over a 25% to 100% duty cycle range has been built and characterised. A maximum average output power of 24.5 W has been achieved at an optical-to-optical conversion efficiency of 43%, with a beam quality factor M2 of 1.1.