Description
Lasers that combine ultranarrow linewidths with high output power over a broad spectral range are critical for quantum technologies and space applications. Diamond Raman Lasers (DRL) with intracavity frequency doubling provide a versatile platform for generating single-frequency, high-power lasers at wavelengths that are hard to reach. This capability is enabled by the frequency shift introduced by the two non-linear processes, and diamond’s exceptional thermal conductivity, high optical damage threshold, and broad optical transparency.
Although Brillouin and Raman lasers share similar coherent scattering dynamics, the much shorter phonon coherence time of the Raman process enables significantly stronger frequency-noise damping, with predicted suppression up to 80 dB, accompanied by corresponding reductions in linewidth [1, 2]. Recently, we demonstrated 60 dB pump noise suppression, allowing multi-watt output powers with Hz-scale intrinsic linewidth at 589 nm [3].
Here, we experimentally demonstrate noise reductions of 78 dB approaching the theory and investigate the fundamental limits of this linewidth-narrowing mechanism by applying controlled phase noise to the pump through selective sideband sinusoidal phase modulation. The experiment uses our recently demonstrated milliwatt L-shape DRL at 589 nm with 1018 nm pump [3]. The frequency noise is measured using the frequency discrimination and the delayed self-heterodyning interferometry techniques [3].
These results establish diamond Raman lasers as a promising route for high-power, ultranarrow-linewidth sources across a wide range of wavelengths. Such sources are attractive for applications in quantum sensing, atomic physics, and space systems, particularly at challenging wavelengths such as 589 nm for sodium laser guide stars.
[1] Debut et al., Phys. Rev. A 62, 023803 (2000); [2] Pahlavani et al., APL Photonics 10, 076107 (2025), [3] Terra et al., arXiv:2603.27191 (2026);
| I am the presenting author | Yes |
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