Abstract

Specific values of quantum defects for nS and nP Rydberg states in alkali metals result in a system of almost equidistant energy levels. Due to this fact two-photon transitions nP → (n+1) P are well described by the three-level scheme with nearly resonant intermediate (n+1) S level. A switching on weak electric field at which quadratic Stark approximation is valid, leads to the virtual and real intermediate states crossing with the double nP → (n+1) S → (n+1)P resonance arising. Bot critical electric field strength and microwave frequency are fixed parameters in this case. Giant dipole momenta values for transitions between nearly Rydberg nP - states lying in microwave region, permit easily to reach saturation parameters much more than unity and also to study the double Stark resonance in strong and superstrong resonant microwave field in frequency scale and electric field strength scale. The fine structure of alkali metal Rydberg nP states results in additional features of the double Stark resonance caused by interaction and interference of quantum transitions.

© 1992 IQEC