I thought this was going to be about phase-conjugate mirrors: https://en.wikipedia.org/wiki/Nonlinear_optics#Optical_phase_conjugation https://en.wikipedia.org/

I thought this was going to be about phase-conjugate mirrors: https://en.wikipedia.org/wiki/Nonlinear_optics#Optical_phase_conjugation https://en.wikipedia.org/wiki/Nonlinear_optics#Optical_phase... Demo here: https://www.youtube.com/watch?v=gAy39ErqV34 https://www.youtube.com/watch?v=gAy39ErqV34