Electronic and photonic states in inhomogeneous media

L. P. Godenko, Vladimir S. Mashkevich

Yu. K. Danileĭko, Aleksandr A. Manenkov, Vladimir S. Nechitailo +1 more

Murray Sargent

Many papers on semiconductor gain media have presented models for two-level homogeneously and inhomogeneously broadened media. In this paper, we show why and where these models become inadequate. The problems originate from the fact that the two-band semiconductor gain medium is an inhomogeneously broadened four-level medium with rapid cross relaxation due to carrier-carrier scattering, and all four levels have appreciable probability in gain media. The four states are given by |n e n h k s>, where n e (= 0 or 1) and n h (= 0 or 1) are the number of electrons or holes, respectively, for momentum k and spin s. The two-level system is a one-electron system with no states corresponding to the partially excited semiconductor states |0 e 1 h k> and |l e 0 h k>, which involve two electrons. The Pauli exclusion principle never gets a chance to enter the picture. In the absence of many-body effects, semiconductor gain can be fitted in an ad hoc fashion by a two-level model, but problems that involve the level probabilities individually, such as the laser photon statistics, elude a two-level description.

Muhammad Danang Birowosuto, S. E. Skipetrov, Willem L. Vos +1 more

Peeter Kukk, A. Freiberg

An analysis and model calculations are presented to clarity how both the electronic and vibrational inhomogeneities with no correlation between them influence the most relevant resonant steady-state third-order nonlinear optical mixing processes (CARS, CSRS, polarization spectroscopy and Raman gain (loss)).It is shown that all these processes may be divided into three groups: 1) processes yielding almost homogeneous spectra: both inhomogeneities are greatly reduced; 2) processes yielding quasihomo- geneous spectra: inhomogeneities are present, but the electronic one is not manifest in the spectrum; 3) processes yielding completely inhomogeneous spectra.The suppression of inhomogeneous broadening allows to study the excited electronic states and the ultrafast relaxation processes in inhomogeneous media more effectively than in linear spectroscopy. * About another steady-state frequency domain technique byhot luminescence measurements for the study of ultrafast energy relaxation see.e. g. f l4 ].ЁЁЗТТ NSV TEADUSTE AKADEEMIA TOIMETISED.30.

Leonid A. Falkovsky, M. E. Alferieff