"Over the last decade, solid-state lasers have been the subject of great interest with a wide range of applications thanks mostly to their superior output-power-to-wall-plug efficiency. However, the limited availability of colours (wavelengths) produced by these lasers forces the user to compromise by utilising a wavelength that is not ideal for the targeted application. Laser systems based on a nonlinear process, called Stimulated Raman Scattering, offer a simple solution to this need. However, the performance and usability of these so-called Raman lasers have traditionally been limited by thermal distortions inherent to the nonlinear process.
This project will, for the first time, investigate the implementation of the adaptive control techniques - typically used in astronomy- inside Raman lasers to significantly alleviate this thermal issue. In this way, the behaviour and performance of the laser can be remotely controlled and optimised resulting in superior performance in terms of output power, beam quality and usability. This offers the prospect of several genuine breakthroughs including a range of world-firsts and world-records as well as the transfer of these laboratory-based systems into an engineering context.
These significantly enhanced systems will address a wide range of applications including astronomy, environmental monitoring, cosmetics and medicine. For instance, the treatment of a variety of skin diseases such as psoriasis or port wine stain removal will strongly benefit from this project.
Finally, knowledge transfer is an important feature of this project with a full strand of activity dedicated to it. The transfer of this technology will be performed within two high profile research groups at Macquarie University, Australia and at the University of Strathclyde. An industrial collaboration with M Squared Lasers will also take place, particularly targeting commercialisation of the final demonstrator."
We have demonstrated the first use of adaptive optics (a well known technique widely used in astronomy) to control and improve high-power solid-state Raman lasers. This led to the development of efficient laser sources operating at wavelengths that are difficult to obtain using traditional gain media. Most notably, power-scaling by ~25% and wavelength selectability of a Nd:YVO4 Raman laser operating in the near-infrared part of the electromagnetic spectrum was reported. In addition, the field of solid-state Raman lasers was also advanced with our report of the first continuous-wave Raman lasers based on a secondary Raman shift.