Character of the saturation, temperature, and spectrum of a two-level system in a strong resonance field

А. В. Леонов, И. Д. Феранчук

Ludmila S. Kancheva, S. Rashev

The splitting of the line of resonance scattered light from atomic systems, being a mong the most interesting phenomena in resonance nonlinear optics has received considerable attention during the past decade [1–11]. It is known by now that the number of lines into which the spontaneous scattered light spectrum splits, grows up with increasing the number N of strongly coupled atomic (or molecular) levels as N(N-1)+1 [10, 11]. But while the character of resonance fluorescence (RF) from a two- and three-level systems has been extensively studied [1–91], the number of papers devoted to the spectral structure of scattered light from systems with N>3 is scarce. In reality there is only one work [12], known to us, which treat s certain aspects of the spectrum of RF from a four-level system irradiated by three strong light fields at exact resonance.

A. R. Kessel, R. N. Shakhmuratov

A. E. Kaplan

J.V. Moloney, William J. Meath

A previously developed exact semiclassical method is used to evaluate multi-photon spectra and Floquet characteristic exponents (dressed-atom energies) for several multi-level systems interacting with both strong oscillating and static fields under varying degrees of saturation. The usefulness of characteristic exponent plots in extracting the physically significant features of the spectrum, without the necessity of evaluating portions of the complete spectrum, is demonstrated for a number of model three-level systems which are not directly amenable to study by the often used rotating-wave approximation. The effect of neighbouring non-resonant states on two-photon resonance profiles is also discussed using three to six level systems (H and Na atoms) as models.

Anatoly I. Burshtein, Anatoly A. Zharikov, S. I. Temkin

The response of a TLS to waves, phase- and frequency-modulated by a purely Markovian process, is calculated rigorously. The spectrum of luminescence characterised by two rates of phase relaxation Gamma 1 and Gamma 2 , rather than one, as in the case of phase diffusion ( Gamma 2 =4 Gamma 1 ), is found. Saturation of TLS and its absorption of light at arbitrary correlation between successive values of its randomly and suddenly varying frequency are determined. The probability of light absorption at any strength of its interaction with TLS and at any rate of frequency modulation is found for uncorrelated frequency change.