Analysis of gain off resonance

Ksenia Dolgaleva, Robert W. Boyd, Peter W. Milonni +1 more

We develop a simple theoretical model for calculating the effective linear susceptibility of composite optical materials with a gain resonance in one of their components. We distinguish two cases of resonant components: the case of “pure resonant emitters,” in which all the atoms or molecules of the resonant medium are of the same sort, and the case of “resonant emitters in a background,” in which only a fraction of the molecules or atoms comprising the resonant component of a composite material are in resonance with the optical field. Analysis of the model suggests that local‐field effects in composite materials can provide a useful means for controlling the optical properties of laser gain media.

Chang-Hee Lee

zahra taheri, Hamideh Kazemi, Mohammad Mahmoudi

Mark C. Phillips, Hailin Wang

Summary form only given. Strong resonant excitation of atoms can lead to Mollow spectra in saturation spectroscopy, with gain near the Rabi sidebands or with a coherent dip at the atomic resonance. In this paper we report experimental studies on the manifestation of Mollow spectra and especially gain in an excitonic system. We observe a spectrally sharp coherent excitonic gain in a semiconductor quantum well under strong resonant excitation. Theoretical analysis based on modified optical Bloch equations (MOBE) indicates that this coherent gain differs qualitatively from its counterpart in atomic systems and is a direct result of exciton-exciton interactions. Understanding the manifestation of Mollow spectra and gain in an excitonic system provides important insight into coherent optical interactions in semiconductors and is of importance in understanding recently observed parametric gain associated with exciton-polaritons in semiconductor microcavities.

Richard M. Friedberg, Sven R. Hartmann, Jamal T. Manassah

Christoph H. Keitel

High-efficiency coherent high-frequency generation via resonant four-wave mixing is investigated in a dressed states analysis of a bichromatically driven three-level system. We propose the existence of exponential gain due to population transfer at the anticrossings of closely spaced inverted dressed states. This occurs when the Rabi frequency of the weaker detuned driving field is much smaller than the leading resonant Rabi frequency and simultaneously comparable to the largest atomic relaxation rate. The dressed population inversion and thus the exponential gain is not affected until the generated field becomes comparable in intensity to one of the two applied fields, when saturation may take place. The analysis is applied to a krypton configuration of interest to current experiments.