We demonstrate a phase-conjugating mirror that has a continuous-wave power reflectivity much greater than unity (gain ~100). This mirror uses nonresonant degenerate four-wave mixing in a single crystal of barium titanate (BaTiO3). With our mirror we have (1) observed cw self-oscillation in an optical resonator formed by this mirror and a normal mirror, (2) demonstrated a cw oscillator that, in spite of phase-distorting material placed inside the resonator, will always emit a TEM00 mode, and (3) demonstrated an optical image amplifier. This mirror will work at any visible wavelength and with weak (milliwatt or weaker) pump beams.
© 1980 Optical Society of America
Original Manuscript: August 19, 1980
Published: December 1, 1980
Jack Feinberg and R. W. Hellwarth, "Phase-conjugating mirror with continuous-wave gain," Opt. Lett. 5, 519-521 (1980)