An exactly soluble model for multiphoton processes. General scheme

Jerzy Zdzisław Kamiński

J. Leo van Hemmen, Kazimierz Rza̧żewski

An exactly soluble model is presented for calculating the mean density matrix of a charged harmonic oscillator in the field of a multimode, high-power laser. Possible applications include multiphoton excitation of the vibrational degrees of freedom of a molecule, dissociation, and the excitation of optical modes in a crystal by chaotic laser light.

Farhad H. M. Faisal

Farhad H. M. Faisal, A. Dalgarno

A N F Aleixo, A. B. Balantekin, M. A. Cândido Ribeiro

A class of bound-state problems which represent the interaction between a system of N two-level atoms and an electromagnetic radiation via an m-photon process is studied, with m = 1; 2; 3;.... We also evaluate some nonlinear effects usually related with the polarisability of the medium and with the dependence on the intensity of the radiation field on the matter-radiation interaction. We obtain exact values for the eigenstates and eigenvalues for all values of total angular momentum of the system and all possible number m of photons involved in the interaction. We give explicit analytic expressions for small numbers of atoms and discuss some aspects of the composition of the eigenstates and of the spectra obtained in these cases.

Zofia Białynicka-Birula

The energy spectrum of electrons resulting from multiphoton ionisation is analysed with the help of a simple, exactly soluble model. The weakening of lower energy lines with the increase in laser intensity, observed in experiments, occurs as a strong-field effect. The dependence of the light shift and the light broadening on the laser intensity and on the virtual-bound transitions in the atom are also analysed.