The Ultrafast Optical Processing Group at INRS (Institut national de la recherche scientifique) has redefined the limitations and constraints for ultra-fast pulsed lasers. As reported in Nature Photonics, researchers from the team of Prof. Roberto Morandotti have produced the first pulsed passively mode-locked nanosecond laser, with a record-low and transform-limited spectral width of 105 MHz—more than 100 times lower than any mode-locked laser to date. With a compact architecture, modest power requirements, and the unique ability to resolve the full laser spectrum in the radio frequency (RF) domain, the laser paves the way to full on-chip integration for novel sensing and spectroscopy implementations.