Nondegenerate resonant multiwave mixing, and frequency-doubled phase conjugation
S. Le Boiteux, J. W. R. Tabosa, Pierre Simoneau +2 more
Nondegenerate four-wave mixing (FWM) has been used for wavelength conversion of optical information.1 In such experiments, two beams F-P (frequency ω1) intersect in a nonlinear medium with a small crossing angle θ (≈ 10 mrad), while a third beam B {frequency ω2) is nearly counterpro- pagating to F [Fig. 1(a)]. This can be viewed as real-time holography with frequency conversion.1 However, the physics differ considerably when the medium is transparent at frequency ω1, as there is no optically induced grating. This occurs when FWM is based on resonant two-photon, ω1 + ω2, absorption (frequencies ω1 and ω2 being resonant with a cascade three-level system and ω1 coupling unpopulated excited states). One interesting feature is that the two-photon coherence is nearly Doppler-free and does not depend much on the θ angle.
Journal of the Optical Society of America B•Jan 1, 1987•0 citations