Henrik Åhlfeldt

Nonlinear optical properties of proton‐exchanged waveguides in z‐cut LiTaO3

Reflection second‐harmonic generation from the polished waveguide end face is used to investigate the second‐order nonlinear optical properties of as‐exchanged and annealed proton‐exchanged waveguides in z‐cut LiTaO3. It is found that proton exchange results in a strongly reduced nonlinearity which, however, can be restored by thermal annealing. Selective etching is used as a method to further investigate the structural changes following proton exchange and annealing. A correlation is found between the etching properties and the nonlinear optical properties. The results are discussed and related to the hydrogen concentration profile using a linear diffusion model for the anneal process.

Postfabrication changes and dependence on hydrogen concentration of the refractive index of proton‐exchanged lithium tantalate waveguides

Postfabricationchanges and dependence on hydrogen concentration of the refractive index ofproton-exchanged lithium tantalate waveguides

Single‐domain layers formed in heat‐treated LiTaO3

Ferroelectric single‐domain surface layers are formed in z‐cut LiTaO3 following heat treatment above the Curie temperature. The polarity of the layers is the same as the polarity of the previously observed domain‐inverted layers formed in heat‐treated LiNbO3. The physical mechanisms behind these two phenomena are believed to be closely related.

Periodic domain inversion and generation of blue light in lithium tantalate waveguides

Generation of blue light from small solid-state light sources is a technological challenge with applications in many areas, among others optical data storage. The authors report frequency doubling using third-order quasi-phase matching in periodically domain-inverted lithium tantalate waveguides. Periodic proton exchange followed by heat treatment caused periodic domain inversion and waveguide formation in a single step. Infrared radiation from a dye laser was coupled through the waveguides and second-harmonic generation corresponding to third-order quasi-phase-matching was observed.<<ETX>>

SINGLE-DOMAIN LAYERS FORMED IN MULTIDOMAIN LITAO3 BY PROTON EXCHANGE AND HEAT TREATMENT

Proton exchange and subsequent heat treatment can yield single‐domain layers at the surfaces of initially multidomain z‐cut LiTaO3. The thickness of these single‐domain layers is equal to the thickness of the domain‐inverted layer that the same processing parameters cause in initially single‐domain samples. This letter also describes how the domain structure develops when heat treatment is carried out above the Curie temperature. The results are discussed in relation to a recently proposed model for the domain‐inversion mechanism.

Novel design for diode-pumped miniature lasers using microstructured silicon carriers

A new design concept for compact diode-pumped solid-state lasers is presented. The design is based on a microstructured silicon carrier with etched v-grooves. This silicon microbench provides efficient thermal management at 10W pumping level, as well as compact integration and alignment of all active and passive optical components of compact diode-pumped solid-state lasers. In initial experiments, a Nd:YAG laser built on the microbench delivered a continuous-wave output of 3W.