Phys.org  January 4, 2023 Widely tunable and narrow-linewidth lasers at visible wavelengths are necessary for applications such as quantum optics, optical clocks, and atomic and molecular physics. At present, the lasers are benchtop systems, which precludes these technologies from being used outside research laboratories. A team of researchers in the US (Columbia University, Tufts University) has demonstrated a chip-scale visible laser platform that enables tunable and narrow-linewidth lasers from near-ultraviolet to near-infrared wavelengths. Using micrometre-scale silicon nitride resonators and commercial Fabry–Pérot laser diodes, they achieved coarse tuning up to 12.5 nm and mode-hop-free fine tuning up to 33.9 GHz with intrinsic linewidths […]