The generation of third harmonic radiation (THG) is required for many pulsed solid-state laser applications in industry and science. In this contribution, the coatings for two necessary optical components, dichroic mirrors and nonlinear optical (NLO) crystals are in the focus of investigation. Because of the high bulk damage threshold lithium triborate (LBO) crystals are applied for this study. HfO2/SiO2 mixtures are employed as high refractive index material to improve the power handling capability of the multilayers. All coatings are produced by ion beam sputtering (IBS) using a zone target assembly for the deposition of material mixtures. The atomic composition and the oxidation ratio of different HfO2/SiO2 mixtures are analyzed by X-ray photoelectron spectroscopy (XPS). The influence of different deposition temperatures and post annealing on the optical properties and the amorphous micro structure of the films is investigated by UV/Vis/NIR spectroscopy and X-ray diffraction (XRD). The laser induced damage thresholds at 355 nm wavelength for nanosecond pulse durations are measured in a 10,000on1 experiment according with the standard ISO21254. Furthermore, the optical components are tested under real application conditions.

Material mixtures offer new possibilities for synthesizing coating materials with tailored optical and mechanical properties. We present experimental results on mixtures of HfO2, ZrO2, and Al2O3, pursuing applications in UV coating technology, while the mixtures are prepared by magnetron sputtering, ion beam sputtering, plasma ion-assisted deposition (PIAD), and electron beam evaporation without assistance. The properties investigated include the refractive index, optical gap, thermal shift, and mechanical stress. The first high reflectors for UV applications have been deposited by PIAD.

We present a long term stable single frequency MOPA with 40 W output power and M-2 < 1.2 consisting of an ultrastable 1 W non-planar ring cavity oscillator with outstanding single frequency characteristics and one Innoslab amplifier stage. The partially end pumped Nd:Y`VO4 Innoslab amplifier is set up in a folded single pass configuration. A 30 GHz tunable spectral bandwidth of 1kHz/100ms and a relative intensity noise (RIN) of < 1 10(-5) Hz(-1/2) (> 10kHz) was measured in free-running mode. Together with an active intensity noise suppression electronics a RIN of < 5 10(-7) Hz(-1/2) (< 10kHz) was achieved. A comprehensive discussion of experimental data is given.

We present beat measurements of two Nd:YAG lasers frequency-locked to thermally shielded room-temperature cavities. By suppressing convection, heat radiation, and heat conduction we reach lower beat-frequency drifts than are currently found in literature. (C) 2001 Optical Society of America.