Spontaneous emission in a cavity

Y. Yamamoto, Susumu Machida, Kazuhiro Igeta +1 more

Peter W. Milonni

Some of the physics of spontaneous emission in cavities is revisited, including the enhancement of the decay rate by the cavity Q, the nature of inhibited spontaneous emission, and the ‘excess noise’ in lossy laser cavities.

Kikuo Ujihara

For pt.IV see J. Phys. Soc. Japan, vol.47, p.217-224 (1982). Spontaneous emission in a lossy one-dimensional cavity is analyzed under the perturbation approximation and the Wigner-Weisskopf approximation. The cavity loss due to output coupling is treated quantum mechanically by the use of a set of continuously distributed radiation modes. The enhancement and reduction factors in the spontaneous emission probability due to the presence of the cavity structure are derived. Interesting transients in spontaneous emission during a time of the order of the cavity decay time are predicted, which leads to an interpretation of the enhancement or the reduction in spontaneous emission in terms of feedback and self-interference effects. The detection of the emitted photon by a detector atom outside the cavity is also discussed.>

I. R. Senitzky

F. De Martini, Michele Marrocco, Paolo Mataloni +2 more

The quantum theory of the spontaneous emission (SpE) from an active microscopic cavity (microcavity) is given with emphasis on mirror separations of the order of the optical wavelength. The theory is based on a complete set of orthonormal-mode functions that include both transverse polarizations and span the infinite three dimensional space that pervades and surrounds the microcavity. SpE rates for different active-dipole orientations and cavity configurations are calculated. The SpE pulse shape detected outside the cavity is shown to be generally nonexponential. A detailed computer simulation of the process is presented on the basis of the given theory in the perspective of our experiment, for a cavity terminated by mirrors bearing either metal- or semiconductor-multilayered coatings. We then report an extensive experimental verification of the theory by adopting an Eu-dibenzoylmethane complex as active medium with SpE from the $^{5}$${\mathit{D}}_{0\mathrm{\ensuremath{-}}}^{7}$${\mathit{F}}_{2}$ line at \ensuremath{\lambda}=6111 \AA{}, under coherent uv excitation at ${\ensuremath{\lambda}}_{\mathit{p}}$=3547 \AA{}. The results show evidence of ``SpE inhibition'' and ``enhancement,'' of nonexponential decay of SpE signals, and of competition with superradiance and stimulated emission. Finally we report the results of an experimental test of the algorithm adopted in all computer calculations of the optical parameters of the multilayered structures used for cavity confinement.

David A. Branning