Simon Hettrick

High-power planar dielectric waveguide lasers

The advantages and potential hazards of using a planar waveguide as the host in a high-power diode-pumped laser system are described. The techniques discussed include the use of proximity-coupled diodes, double-clad waveguides, unstable resonators, tapers, and integrated passive Q switches. Laser devices are described based on Yb3+-, Nd3+-, and Tm3+-doped YAG, and monolithic and highly compact waveguide lasers with outputs greater than 10 W are demonstrated. The prospects for scaling to the 100 W level and for further integration of devices for added functionality in a monolithic laser system are discussed.

The Software Sustainability Institute: Changing Research Software Attitudes and Practices

To effect change, the Software Sustainability Institute works with researchers, developers, funders, and infrastructure providers to identify and address key issues with research software.

Investigation of neodymium-diffused yttrium vanadate waveguides by confocal microluminescence

We report on the confocal microspectroscopic characterization of planar optical waveguides fabricated in yttrium vanadate (YVO4) crystals by thermal diffusion of neodymium ions. We have found that the waveguide formation is accompanied by Nd3+ fluorescence quenching and by a redshift of the Nd3+ sub-Stark transitions. These effects have been explained in terms of the high Nd3+ concentrations achieved close to the diffusion surface, which lead to the appearance of nonradiative processes, as well as to a local compression in the surroundings of the indiffused Nd3+ ions. By comparing with previous works, we have estimated an equivalent residual stress of 0.1 GPa. The possible mechanisms at the origin of waveguide formation have been also discussed.

An experimental comparison of linear and parabolic tapered waveguide lasers and a demonstration of broad-stripe diode pumping

This paper compares the laser performance of linear and parabolic tapered waveguides in ion-exchanged Nd:Glass, finding significant advantage for the linear guides, with demonstrated adiabatic expansion to widths of 250 /spl mu/m. The characterization of these waveguide lasers by Ti:sapphire pumping is followed by a demonstration of high-power diode-pumped laser operation and a discussion of the optimization of such a scheme for producing high-power integrated-optics laser sources.

Fourth Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE4)

This article summarizes motivations, organization, and activities of the Fourth Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE4). The WSSSPE series promotes sustainable research software by positively impacting principles and best practices, careers, learning, and credit. This article discusses the code of conduct; the mission and vision statements that were drafted at the workshop and finalized shortly after it; the keynote and idea papers, position papers, experience papers, demos, and lightning talks presented during the workshop; and a panel discussion on best practices. The main part of the article discusses the set of working groups that formed during the meeting, along with contact information for readers who may want to join a group. Finally, it discusses a survey of the workshop attendees.

Nd:glass tapered planar waveguide laser

We have demonstrated the first use of a tapered waveguide in a planar dielectric geometry. The Nd/sup 3+/-doped BK7 glass laser had a threshold of 15mW, and a slope efficiency of 42% for a 20% output coupler when end-pumped by a Ti:sapphire laser.

Ion-exchanged Nd:glass tapered waveguide laser

Summary form only given. We describe the laser operation of tapered waveguides based on ion-exchanged Nd:BK7 glass. A tapered waveguide is of interest as it could allow end-pumping with broad-stripe diodes and, for materials with a strong pump absorption, side-pumping with high power diode bars. If the taper is combined with a single-mode channel and adiabatic expansion of the lowest-order spatial mode can be achieved then there is good potential for simple and compact, high-power sources with good output beam quality. The output beam from the broad planar end of the taper was measured to be /spl sim/1.5 times diffraction limited in both planes, while the output from the normal channel guide was /spl sim/1.0 and /spl sim/1.2 times diffraction limited in the horizontal and vertical planes respectively. The prospects for compact, diode-pumped lasers of high beam quality based on adiabatic tapered waveguides are discussed.