A prism reflector of anti-resonant ring configuration

Two identical prisms are combined to form an anti-resonant ring reflector, giving total reflection without the use of coatings or roof edges. When used as the total reflector in a Q-switched Nd:YAG laser this device has shown a damage threshold twice that of a multilayer reflector

Guided wave optics in periodically poled KTP: quadratic nonlinearity and prospects for attosecond jitter characterization

For the first time to our knowledge, continuous nonsegmented channel waveguides in periodically poled KTiOPO4 with guided orthogonal polarizations are used to demonstrate type II background-free second harmonic generation in the telecom band with 1.6%/(W cm2) normalized conversion efficiency. This constitutes a 90-fold improvement in aggregate conversion efficiency over its free space counterpart. Simulations show that the guided wave device should enable the measurement of timing fluctuations of optical pulse trains at the attosecond level in an optical cross correlation scheme

Upconversion-induced heat generation and thermal lensing in Nd:YLF and Nd:YAG

We investigate the influence of interionic upconversion between neighboring ions in the upper laser level of Nd:YLF and Nd:YAG on population dynamics, heat generation, and thermal lensing under lasing and non-lasing conditions. It is shown that cascaded multiphonon relaxations following each upconversion process generate significant extra heat dissipation in the crystal under non-lasing compared to lasing conditions. Owing to the unfavorable temperature dependence of thermal and thermo-optical parameters, this leads, firstly, to a significant temperature increase in the rod, secondly, to strong thermal lensing with pronounced spherical aberrations and, ultimately, to rod fracture in a high-power end-pumped system. In a three-dimensional finite-element calculation, excitation densities, upconversion rates, heat generation temperature profiles, and thermal lensing are calculated. Differences in thermal lens power between non-lasing and lasing conditions up to a factor of six in Nd:YLF and up to a factor of two in Nd:YAG are experimentally observed and explained by the calculation. This results in a strong deterioration in performance when operating these systems in a Q-switched regime, as an amplifier, or on a low-gain transition. Methods to decrease the influence of interionic upconversion are discussed. It is shown that tuning of the pump wavelength can significantly alter the rod temperature