Diamond Enhances Laser Beams

Diamonds just might be a laser beam’s best friend.

A team from Macquarie University’s Photonics Research Center has discovered how to increase the quality of high-power laser beams by exploiting the optics of an 8-mm diamond.

The diamond-laser device made the brightness of the output beam 50 percent higher than its input beam. Courtesy of Macquarie University.

A 50-W neodymium laser pump beam operating at 1064 nm and pulsed at 36 kHz was converted via stimulated Raman scattering to produce a 1485-nm output beam of 16.2 W — at an overall conversion efficiency of 40 percent. While the input beam had a relatively low quality factor (M² = 3 to 4), the output beam achieved a quality factor of M² = 1.17 ± 0.08, resulting in a higher overall brightness.

Researchers said diamond has the ability to dissipate heat more quickly than other optical materials and is transparent across a broad spectrum, which allows converters for a wide range of laser wavelengths and applications.

“Diamond is a very exciting laser material,” said Dr. Aaron McKay. “Its properties in so many aspects are so much better than other materials that there are likely to be massive opportunities for greatly improving laser capability.”

The technique enables the conversion of high-power lasers with poor beam quality into bright beam devices emitting in the eye-safe IR region. This type of high-quality laser could meet demands in applications such as materials processing, environmental and remote sensing, and defense and security, researchers said.

The work was supported by the Asian Office of Aeronautical Research and Development. The research is published in Laser & Photonics Reviews (doi: 10.1002/lpor.201400012).