Theoretical concept for generating exceptionally stable laser light without the need for traditional mirrors or an optical cavity could soon be tested

https://phys.org/news/2025-10-mirrorless-laser-physicists-source.html

"superradiant emission uses atoms as quantum emitters that build their own feedback mechanism/ frequency selection via dipole-dipole interaction... pumping only fraction of emitters with laser energy causes synchronized collective radiation, remaining unpumped passive emitters act as frequency-selective feedback for active emitters... takes place of traditional optical resonator... highly directional, spectrally pure... nanophotonics, precision measurements, quantum sensors/ clocks, on-chip devices"