🚀 go-pugleaf

With all this talk about mirrors reversing, I was wondering if anyone
has discussed phase-conjugate mirrors here? My understanding of these
nifty devices (gleened from only a single Sci. Amer. article) is that
they reflect light without making it 180 degrees ou tof phase. This has
the benifit of making transmition interference reversible, etc. The most
astounding demonstration was the "spatula air laser". Air was used as
the lasing medium, with a phase-conjugate mirror at one end, and a
common stainless steel kitchen spatula. Another thing I remember was
that in the same experiment, a technician discovered to his dismay? that
some reflective thing he was wearing also formed one end of a lasing
column. Great article, I'll have to go home & find the date.
Any one else know more about these things?