Associate Professor Richard Mildren and his colleagues at the Macquarie University Photonics Research Centre (Australia) have demonstrated diamond lasers with efficiency higher than almost all other materials
“The major achievement is that we are able to use synthetic diamond to create high performing laser devices,” Mildren said. “We are now in good position to explore the highly exotic laser properties of diamond, many of which are not so widely appreciated.
The diamonds used in the laser research are colourless, approximately eight millimetres long, and weigh a bit less than a carat. They are grown to the researcher’s specifications using a process called chemical vapour deposition that essentially creates the crystal lattice carbon by carbon atom and layer by layer on top of a large flat diamond crystal substrate. The synthetic diamond forms the core component of what is called a Raman laser, a type of laser that is optically stimulated rather than electrically powered.
“Though there has been little take up of this type of diamond in the gem market, it is very well suited to our purposes. Diamonds larger than one centimetre are likely to be available very soon which will also be an advantage for our studies.”
Diamond is also the most transparent material known to man, in terms of the range of light wavelengths (or colours) that can pass through the material. Mildren said this would enable researchers to select from a huge range of laser wavelengths, such as in the far infrared, and hence potentially tap into a broad range of applications.
“The wide wavelength or colour choice means that we can tackle key challenges facing society in several areas. I’m aiming to attract junior researchers to start investigating devices that might solve key challenges in neurosurgery, or to safely detect toxic or explosive gases from a distance, a challenge that is considered a major priority for defence and counter terrorism organisations,” Mildren said. Mildren said satellite borne diamond lasers for mapping greenhouse gases in the atmosphere were also a possibility