Fluorescence versus laser effect: Towards a unified theory

Jacob Szeftel, Antoine Khater, Nicolas Sandeau

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    A single evolution equation is established to treat the mechanisms of fluorescence and the laser effect, using a mixed representation, classical for the electromagnetic field and quantum for the dipoles. The model approach takes advantage of the principle of conservation of energy for the system of electromagnetic field and dynamic dipole. A resulting nonlinear differential equation is derived and is shown to sustain two fixed points associated with fluorescence and laser emission. The existence of a pumping threshold is confirmed for the laser effect. In particular the pumping rate determines whether light will be emitted by fluorescence or by the laser effect, and there is no pumping that engenders fluorescence and laser emission simultaneously. The initial physical conditions, chosen to integrate the evolution equation in time, assume a nonvanishing electric polarization of the emitting dipole rather than a nonvanishing electromagnetic field. The distribution function accounting for the thermal fluctuations of the random initial polarization is also calculated.

    Original languageEnglish
    Pages (from-to)4602-4608
    Number of pages7
    JournalOptics Communications
    Issue number23
    Publication statusPublished - 1 Dec 2009



    • Fluorescence theory
    • Laser theory

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Atomic and Molecular Physics, and Optics
    • Physical and Theoretical Chemistry
    • Electrical and Electronic Engineering

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