Photonics Breakthroughs 2024: Narrow-Linewidth Lasers in the Visible and Near-Infrared

Narrow-linewidth lasers enable a variety of highprecision applications, such as sensing, optical clocks, and microwave frequency generation. Advances in photonic integration in the last decade led to the development of ultra-lownoise integrated semiconductor lasers, mostly in the telecom wavelength range. In recent years, the demand for highperformance lasers at shorter wavelengths skyrocketed, driven by applications in sensing and atom trapping. Low-noise lasers are of particular importance in this spectral range, as they are essential for optical clocks. Here, we will review recent progress in narrow-linewidth lasers at shorter wavelengths, present results on a hybrid-integrated low-noise laser at 780 nm and discuss the perspectives and challenges of high-performance semiconductor lasers in the visible and near-infrared.