Abstract
The nonlinear response of Na vapor subjected to strong laser fields is characterized by a multitude of nonlinear processes, including parametric four-wave mixing (PFWM), stimulated hyper-Raman scattering (SHRS) of the pump field, and Raman scattering of the PFWM fields. The observation of double-peaked gain profiles for two-photon resonant optical phase conjugation and SHRS and a deviation from the exponential pump-power dependence of SHRS suggest that the atomic response is also strongly influenced by AC Stark shifts induced by the SHRS field with a frequency close to the 4D-4P transition. Results of a measurement of the phase-conjugate reflectivity near the two-photon resonance are shown for a pump intensity of 3.4 × 107 W/cm2 and two different sodium number densities. The same transition from a single- to a double-peaked spectrum is observed when increasing the pump intensity at a sodium pressure of 2 torr. PFWM is strongly suppressed due to phase-matching conditions, and shifts induced by the laser field can be neglected. However, SHRS occurs simultaneously. Inclusion of the AC Stark shift of the 4D state in the atomic equation of motion results in a similar reduction factor for the phase-conjugate reflectivity, and qualitative agreement with observations is obtained.
| Original language | English |
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| Pages | 142-144 |
| Number of pages | 3 |
| State | Published - 1990 |
| Event | 17th International Conference on Quantum Electronics - IQEC '90 - Anaheim, CA, USA Duration: May 21 1990 → May 25 1990 |
Conference
| Conference | 17th International Conference on Quantum Electronics - IQEC '90 |
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| City | Anaheim, CA, USA |
| Period | 05/21/90 → 05/25/90 |