Josef Robert Unternahrer

Performance of a degenerate KTiOPO 4 optical parametric oscillator, synchronously pumped by a mode-locked and Q-switched Nd:YAG continuous-wave oscillator–slab amplifier combination

We used a cw-pumped, Q-switched, and mode-locked Nd:YAG oscillator and a cw-pumped, multipass traveling-wave amplifier with a face-pumped total-internal-reflection Nd:YAG slab as the gain element to produce an 80-W, TEM00 diffraction-limited beam at a Q-switching rate of 10 kHz (50 W at 3 kHz). The output of this device was used to synchronously pump a degenerate optical parametric oscillator that utilized six KTiOPO4 crystals as nonlinear converters. A maximum average power of 14 W at 2.128 μm was generated with a conversion efficiency of 25% at 4.25 kHz.

High efficiency, high average power intracavity harmonic generation in a diode-pumped Nd:YAG laser oscillator

Stable, high beam quality intracavity second harmonic generation to average power ≥ 200 W at 532 nm and ≥ 14% diode-to-output efficiency has been demonstrated in a diode-pumped Nd:YAG laser oscillator using lithium triborate.

High-average-power solid state deep-UV lasers for medical applications

We present the results of an experiment to demonstrate high average power uv radiation at 266 and 213 nm obtained from the fourth and fifth harmonics of a Nd:YAG laser. The second harmonic of the infrared laser was generated in an LBO (lithium triborate) crystal, the fourth harmonic by doubling the output of the LBO in a BBO (beta barium borate) crystal, and the fifth harmonic was obtained by sum frequency mixing of the fourth harmonic and the fundamental beam in another BBO crystal. In this paper we report high average power uv radiation at 266 nm (1.3 W) and at 213 nm (0.54 W). To our knowledge, these are the highest powers ever achieved at these wavelengths in an AO Q-switched, Gaussian single-mode Nd:YAG system.