“…In addition, the atomic clocks, e.g., based on Rb and Cs transition lines, require laser sources with narrow linewidth and a certain frequency in the visible range. Among the other important applications that need narrow-linewidth visible lasers, one can mention quantum photonics, including quantum sensing and communications 24 , 25 , high-capacity communication systems 26 , laser-based position/navigation/timing systems 27 , 28 , laser-based displays 29 inclusive of displays for augmented reality and virtual reality 30 .…”