Phase conjugation of microsecond pulses by forward Brillouin scattering

We have conducted an experimental study of phase conjugation of microsecond laser pulses via forward Brillouin scattering in the field of two intersecting pump beams whose transverse structures closely resemble that of a single mode. We have demonstrated that an interaction can take place at relatively low pump power densities. It thus becomes possible to achieve phase conjugation of long pulses without competition from thermal self-effects.