Ultrashort Pulse Lasers and Amplifiers Based on Nd:YVO₄ and Yb:YAG Bulk Crystals

Abstract

This Chapter focuses on the generation of ultrashort pulses and their amplification to high energies in Nd:YVO₄ and Yb:YAG bulk crystals. Particularly with regard to applications such as high-precision micromachining, we briefly describe why these materials can be a promising alternative for current systems mostly based on Ti:sapphire, and how the actual setup of a laser would benefit from the possible simplifications. Following this, recent progress in the development of high-power diode-pumped picosecond Nd:YVO₄ and femtosecond Yb:YAG oscillators is briefly outlined. Mode locking of the lasers presented here is achieved with either semiconductor saturable absorber mirrors (SESAMs) or by employing phase self-adjusted mode locking (PSM). The setup and the characterization of a Nd:YVO₄ regenerative amplifier is subsequently explained in detail and experimental results are presented. The output of the amplifier is also frequency converted to the visible spectral range by second-harmonic generation (SHG) in LBO and to the UV by fourth-harmonic generation (FHG) in BBO. For higher average output powers in the IR and to demonstrate the potential of a further power scaling, an additional single-pass amplifier is applied to the system.