degenerate four-wave mixing


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degenerate four-wave mixing

[di′jen·ə·rə·rət ′fȯr ‚wāv ′mik·siŋ]
(optics)
A method of achieving optical phase conjugation in which two strong counterpropagating pump beams, having the same frequency, set up a standing wave in a clear material whose index of refraction varies linearly with intensity, thereby providing the conditions in which a third beam, at the same frequency, incident upon the material from any direction, results in a fourth beam which precisely retraces the third one.