Fundamental linewidth of an AlN microcavity Raman laser

Raman lasing can be a promising way to generate highly coherent chip-based lasers, especially in high-quality (highQ) crystalline microcavities. Here, we measure the fundamental linewidth of a stimulated Raman laser in an aluminum nitride (AlN)-on-sapphire microcavity with a record Q-factor up to 3.7 million. An inverse relationship between fundamental linewidth and emission power is observed. A limit of the fundamental linewidth, independent of Q-factor, due to Raman-pump-induced Kerr parametric oscillation is derived. (c) 2022 Optica Publishing Group

Automated summary

In this study, we measured the fundamental linewidth of a laser in high-quality crystalline microcavities, and found an inverse relationship with the emission power. We also derived the limit of the fundamental linewidth, independent of the Q-factor. These findings are important for the development of highly coherent chip-based lasers.