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Light absorption at high intensities. Comparison of quantum theory and semi‐classical results
Author(s) -
Schurr J. Michael
Publication year - 1976
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560100213
Subject(s) - semiclassical physics , physics , resonance (particle physics) , amplitude , absorption (acoustics) , quantum , phase (matter) , dipole , intensity (physics) , radiative transfer , light intensity , atomic physics , radiation damping , quantum electrodynamics , radiant intensity , quantum mechanics , radiation , optics
Abstract An error in the author's previous treatment of the interaction of an absorber with high intensity light is noted. The correct development of Mower is applied to determine the amplitude of the initial state of the radiation‐matter system. Comparison of the quantum theory solution for a damped absorber exposed to a square light pulse with the results of semiclassical theories based on the undamped optical Bloch equations is effected by determining the effective in‐ and out‐of‐phase components of the transition dipole response. In general, the out‐of‐phase (or absorptive) part of the transition dipole is zero at the outset and strongly time‐dependent at short times, evolving to a steady‐state value at longer times. For resonance radiation the system exhibits either overdamped irreversible decay or underdamped oscillations, depending upon the relative magnitudes of the incident light intensity and the radiative damping rate. Specific results are presented for a variety of limiting values of the physical parameters, including light intensity, damping rate, and amount of off‐resonance.