Influence of stimulated line broadening and stimulated line shift on multiphoton processes

Shaul Mukamel

W. R. Garrett

Yu. M. Kirin, Yu. N. Popov, Sergei G Rautian +2 more

An investigation was made of the infrared emission spectra of potassium vapor illuminated with giant ruby laser pulses and with the Stokes component of the stimulated Raman scattering of these pulses in nitrobenzene. These emission spectra were recorded after conversion to visible light in a nonlinear crystal. It was found that the dependences of the intensities, widths, and shifts of the infrared lines on the vapor pressure of potassium had extrema. The broadening and shift were induced by the field. The results obtained indicated a considerable importance of six-photon parametric processes in the emission of infrared potassium lines.

Karim Faid

A complete stochastic theory of relaxation is developed in terms of a homogeneous equation for the averaged density matrix of a system immersed in a thermal bath.\nThis theory is then used as the basis of a new stochastic approach to the phenomenon of collisional broadening of spectral line shapes. Single photon and multiphoton processes are studied.\nThe features of a line shape are linked by simple expressions to the statistical properties of a stochastic hermitian Hamiltonian. The ordinary line shape predicted by Kubo's approach is generalized. The present approach predicts broadening as well as asymmetry and shift. A representation of line shapes in multiphoton processes by diagrams is also developed.

A. T. Georges, P. Lambropoulos

Farhad H. M. Faisal, A. Dalgarno