Resonant Raman Scattering and Luminescence

T. Takagahara

Eiichi Hanamura, T. Takagahara

W. Werncke, A. Lau, M. Pfeiffer +3 more

T. Takagahara

Resonance Raman scattering and luminescence under an intense excitation field are studied for both stationary and transient excitation regimes. By means of the Green function theory of resonance Raman scattering and luminescence we explain the characteristic features of the recent experiments on two-photon resonance Raman scattering via excitonic molecule in CuCl where the resonance dip and the asymmetry of the Raman yield around the resonance were observed. We ascribe the origin of the resonance dip of the Raman yield to the resonance enhancement of collisional damping of excitonic molecule and exciton states. The asymmetry of the Raman yield can be naturally understood in terms of the frequency and wave-vector dependent relaxation constants. Furthermore an approach is proposed which incorporates the coherence and correlation among excitonic molecules and excitons in their non-equilibrium state and clarifies their effects on the optical spectra.

S. Abraham-Ibrahim, B. Caroli, C. Caroli +1 more

We study the competition, in the light scattering spectrum, between electronic resonant Raman scattering and luminescence, on a simple three-level model due to Takagahara et al., where electrons are assumed to couple, in the intermediate state, with a field of localized « phonons ». The model can be solved exactly. We show that the relative weight of Raman versus luminescence peaks is controlled by a single memory parameter γb /Γ — where γb and Γ are the damping rates of the intermediate electronic state and of the phonons. If γb/Γ >> 1, memory is quasi-perfect, and the spectrum is purely Raman; in the opposite limit luminescence predominates. For γb/Γ ∼ 1, both structures are present, as well as anomalous satellites characteristic of « hot » luminescence.

Peeter Saari