Semiclassical formalism for the treatment of three-level systems

Vladimir V. Demchenko, N.M. El-Siragy

G.-D. Willenberg, J. Heppner, Frank B. Foote

The semiclassical density matrix treatment is applied to serial four-level systems for the steady state. Phase and energy relaxations as well as Doppler effects andMdegeneracy are accounted for. The calculations are restricted to parallel polarized fields, avoiding problems of quantum interference. The formalism is used to calculate the gain spectra of different four-level far-infrared (FIR) laser schemes: double resonance pumped laser, Raman laser, two-photon pumped laser, and hyper-Raman-laser.

Motowo Tsukakoshi

A semiclassical treatment of four-wave mixing is presented for the case for which a two-frequency pump wave of arbitrary intensity and a weak probe wave interact with a three-level system. Numerical, as well as analytical, results for the emission spectra are obtained from the steady-state response. At high pump power, the spectra are strongly modified by the ac Stark effect.

Christian Grosche, Frank Steiner

Lorenzo J. Curtis

Kwanghsi Wang, Tak‐San Ho, Shih‐I Chu

The authors present an exact treatment of two- and multiquantum transitions in three-level systems driven by two intense linearly polarised monochromatic fields based on the semiclassical many-mode Floquet theory developed recently. Further they extend the almost degenerate perturbation theory of Salwen (1955-6) to the two-mode Floquet Hamiltonian and obtain approximate analytical formulae for multiphoton transition probabilities, resonance bichromatic shifts and widths, and absorption lineshapes beyond the conventional rotating-wave approximation (RWA). Detailed comparison of the analytical, the RWA, and the exact results is given. Several novel features of multiphoton lineshape characteristics are pointed out.