Scientists in Australia have achieved highly efficient diamond Raman laser performance using low birefringence, high optical quality synthetic diamond, supplied by Element Six.
Substantial progress in the performance of a pumped external cavity diamond Raman laser has been reported in a letter published in the current issue of Optics Letters (Optical Society of America) by Richard Mildren of the MQ Photonics Research Centre, Macquarie University and Alexander Sabella from the Defence Science and Technology Organisation in Australia.
These scientists have used high optical quality single crystal synthetic diamond material developed by Element Six in Ascot for a diamond Raman laser design. The 532nm external cavity laser generated output at 573nm, the first Stokes, shifted frequency, with a photon conversion efficiency >90 per cent. They reported that the efficiency of the system was 'commensurate with the highest previously reported for other Raman materials pumped by Q-switched lasers'.
In relation to the synthetic diamond from Element Six, the authors note: 'The recent availability of high optical quality synthetic material is currently enabling a surge of interest in diamond Raman laser development.' For Raman lasers, diamond has three main properties that make it suitable as a laser optic material – high thermal conductivity, high Raman gain and broad optical transmission.
A vital property of the diamond supplied by Element Six is that it exhibits ultra-low birefringence (measured to be 1×10-7) and has a thermal conductivity that is two to three orders of magnitude better than typical Raman active crystals. In addition, diamond shifts the wavelength slightly further than the Raman-active crystals that are currently used which may also extend its application potential.
This exceptional performance has been achieved through a development programme by Element Six that has concentrated on three aspects of diamond product fabrication – material growth, a carefully developed processing route and consistency of the final product.