Fibre-Laser Pumped Diamond Raman Lasers for Lidar and Clear Plastics Welding

"Diamond and fibre are a natural match that provides a platform to take high-power lasers into hitherto unattainable parameter regimes and to serve new applications. Though attractive in its simplicity, this area remains largely unexplored. Here, we propose a partnership that will enable high-impact applications through careful investigation of the underpinning device science. This will lead to fibre-pumped diamond Raman lasers with properties tailored to applications in LIDAR and clear plastics processing. We aim to lay the foundations for this to become the preferred approach for a number of important laser applications.

Fibre lasers are the laser of choice from medicine to materials processing thanks to their reliability, low cost of ownership, proven performance, and outstanding power scalability. While moderate laser parameters and standard wavelengths suffice for many applications, many more require better beam quality, narrower line widths, specific wavelengths, or well-controlled high-energy pulses - but still at hundreds of watts of output power. Fibre lasers can only rarely simultaneously satisfy these requirements. In this project, we aim to overcome these generic limitations of fibre sources by employing diamond to shift fibre lasers further into infrared via stimulated Raman scattering (SRS) with simultaneous brightness enhancement and, in the case of pulses, spectral narrowing towards the transform-limit.

The UK is established as a world leader in fibre laser research and has played a leading role in pioneering the use of diamond in Raman lasers. Both fibre lasers and diamond are recognized as being superbly power scalable thanks to superior optical and thermal properties. Our approach will harness the advantages of fibre systems - efficiency, compactness, and reliability - while modifying their output to better address key industrial challenges. While the combination of fibre and diamond is a platform solution that can address a wide range of wavelength-specific applications, especially in the near IR range, in this project we aim to prove the technology in two areas that are important for our industrial partners. This proposal will deliver a new type of laser that is uniquely capable of the combination of power, brightness, spectral purity and wavelength required for industrially important applications in LIDAR and clear plastic processing."

14th February 2019 This project is ongoing and so no final conclusion has been reached. However, the key objective of pumping a diamond Raman laser operating at >1.5um with a pulsed fibre laser has recently been achieved and work is underway to build on this. On the 2.5um laser side of the project, a proof of principal demonstration of a diamond Raman laser has been achieved and progress awaits the demonstration of the fibre laser pump by our collaborators.