Multiphoton processes in lambda three-level systems

Michał Berent

Michał Berent, R. Parzyński

We generalize our analytic approach (Berent, M. and Parzyński, R. (2009): Phys. Rev. A (80) 033834) to include the effect of strong depopulation of the initial state when considering the multiphoton population transfer and scattering of low-frequency light by a 3-level system in the lambda-type configuration. We discuss the quality of the approximations made, i.e., the adiabatic and generalized rotating-wave approximations.

P. Lambropoulos, Stephen J. Smith

Ying Wu, Xiaoxue Yang

By using an efficient approach developed by us, we present explicit analytical expressions for all the eigenenergies and eigenstates in terms of a parameter lambda for a class of models describing three-mode multiphoton processes. The parameter lambda is shown to be determined by the roots of a simple polynomial. We also obtain the exact explicit analytical expressions of infinite eigenstates and eigenenergies without any unknown parameters.

A. M. Bonch-Bruevich, V. A. Khodovoǐ

Hartmut Wallis

A subharmonic resonance occurs on irradiation of a three-level (\ensuremath{\Lambda}) system by two bichromatic fields when an integer multiple of the common frequency difference matches the Raman detuning between the two lower levels. The occurrence of these multiphoton resonances requires saturation of the Raman transition. The three-level model is applied in order to understand recent experimental studies of subharmonic Raman resonances between vibrational states of optically trapped atoms. I explain the difference between these resonances and the well-known velocity-tuned (Doppleron) resonances in two-level atoms by considering a two-state model with the excited state eliminated. I finally point out a Sisyphus cooling mechanism that is entirely dependent on an additional relaxation of the Raman coherence, comparable to collision-induced resonances.