Phys.org  March 28, 2023 Optical parametric oscillators are widely used to generate coherent light at frequencies not accessible by conventional laser gain. However, chip-based parametric oscillators operating in the visible spectrum have suffered from pump-to-signal conversion efficiencies typically less than 0.1%. A team of researchers in the US (NIST, University of Maryland) demonstrated efficient optical parametric oscillators based on silicon nitride photonics that address frequencies between 260 and 510 THz. Pumping silicon nitride microrings near 385 THz yielded monochromatic signal and idler waves with unprecedented output powers in this wavelength range. They estimated on-chip output powers (separately for the signal […]