Diamond Brillouin lasers provide high power, low noise

Brillouin lasers, which achieve optical gain through stimulated inelastic scattering, are an emerging tool in multiple fields because they exhibit advantageous properties compared to other types of lasers, including a built-in mechanism for reducing phase noise. A disadvantage of these lasers is that they typically need to be paired with guided wave structures. However, by combining a Brillouin laser with diamond, Bai et al. were able to operate the laser without acoustic or optical guidance.

When the authors ran their Brillouin laser in diamond without guided wave optics, the output power was ten times higher than the highest previously reported value for a continuous wave Brillouin laser. The diamond Brillouin element also features low quantum defect and high thermal conductivity, which allows a wide range of potential output powers.

“We expect the importance of our work to be broad in the field of optics based on the pressing need for lasers with wide power range and high-fidelity frequency properties,” said author Richard Mildren. A high-power diamond Brillouin laser could be especially useful for narrow-linewidth lasers and generating millimeter waves with low phase noise.

Due to its frequency shift, the diamond Brillouin laser system could be a new alternative to state-of-the-art millimeter-wave-generation techniques, with the benefits of higher power and reduced phase noise. Brillouin lasing’s noise reduction could also act as a linewidth narrowing converter for applications in quantum processing, gravitational wave astronomy, microwave photonics and spectroscopy.

Source: “Diamond Brillouin laser in the visible,” by Zhenxu Bai, Robert J. Williams, Ondrej Kitzler, Soumya Sarang, David J. Spence, Yulei Wang, Zhiwei Lu, and Richard P. Mildren, APL Photonics (2020). The article can be accessed at https://doi.org/10.1063/1.5134907 .