Resonance condition electrodynamics

This effect, which had been predicted by quantum electrodynamics, can intuitively be understood as follows in the resonant case, that part of the thermal radiation field that is in the resonant cavity mode can contribute to stimulated emission in the transition ) n — ), resulting in a shortening of the lifetime (Sect. 11.3). For the detuned cavity the fluorescence photon does not fit into the resonator. The boundary conditions impede the emission of the photon. If the rate dN/dt of atoms in the level n) behind the resonator is measured as a function of the cavity resonance frequency cu, a minimum rate is measured for the resonance case co = coo (Fig. 14.49). 

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