Ultra-Short Pulse Laser Welding of Dissimilar Materials

Optical systems are used in an enormous range of products and devices. A well-known problem in the assembly of these devices is how to join the optical components to structural materials like metals. Enormous effort has gone into developing reliable, repeatable bonding methods which are often dependent on the introduction of some form of interlayer like a solder or frit. Nevertheless, these methods have issues, with the introduction of interlayer materials inducing serious issues in terms of outgassing, creep, accuracy, aging and the introduction of stress-induced birefringence to the optics.

Ultra-short pulse laser welding is an emerging technique that provides a direct fusion weld without the requirement for difficult pre-processing steps. Heriot-Watt University has carried out ten years of research aimed at developing this process, including investigating surface preparation, laser parameters, lifetime performance, and direct measurement of stress-induced phase retardation (birefringence) using a polariscope we have developed and deployed in-house. In this webinar, Richard Carter will give a presentation focused on recent developments including material combinations and the measurement/ analysis of weld-induced stress within the optical components, as well as thermal-induced stress under environmental temperature cycling.

What You Will Learn:
• Capabilities and limitations of ultra-short pulse laser welding
• Magnitude of stress in optical mountings via a state of the art polariscope

Who Should Attend:
• Optical system designers
• Optical system manufacturers
• Those interested in resolving polarisation effects in situ

About the Presenter: Richard Carter from Heriot Watt University

Richard joined the high power laser applications group at Heriot-Watt as a research associate investigating laser based production processes. He was one of the founding members of the EPSRC Centre for Innovative Manufacturing in Laser Based Production Processes. In 2018 was appointed a Research Fellow (Lecturer) within the Institute for Photonics and Quantum Sciences at Heriot-Watt University and in 2021 promoted to his current role as Associate Professor with teaching responsibilities in both Physics and Mechanical Engineering. His research interests revolve around precision laser manufacturing, optical system automation and fibre optics. Recent projects have included: high power beam delivery with novel hollow core fibre optics; fibre optic environmental sensing; micro material processing including machining, drilling and welding; microwelding of highly dissimilar materials; the use of robotics to align optical systems and novel beamshaping techniques.