Applications Of Closed-orbit Theory To The Spontaneous Emission Of Atoms In Dielectric Slabs

In this paper, the spontaneous emission rate of an atom in dielectric systems with a single interface and two interfaces is calculated by the use of quantum electrodynamics and analyzed, for the first time, by the use of closed-orbit theory, which has been successfully used to explain the behavior of electrons in atom and molecule physics. Closed-orbit theory gives us a new way to understand the spontaneous emission rate of an atom concisely and reasonably.In the case of a single interface, the spontaneous emission rate is shown to exhibit a single-periodic damping oscillation as the atomic distance from the interface is incr-. eased. From the closed-orbit theory, there is only one kind of closed-orbit in this case. The frequency of the oscillation is correctly predicted by the closed-orbit theory. This is the first time to apply the closed-orbit theory to optics. This study provides a different perspective for the spontaneous emission of atoms in the presence of environments.Using closed-orbit theory, we also study the spontaneous emission rate for the c-ase of two interfaces and discuss the variations of the spontaneous emission rate of an atom with the thickness of the slab. The calculated results show that the spontaneous emission rate displays multi-periodical oscillations with the variation of the thickness of the slab, when the ratio of distances from the emission atom to the upper and lower interfaces is fixed. The frequencies of oscillations are obtained by Fourier transform and each frequency corresponds to each closed orbit of photon going out from the ato-m and returning to the atom. The difference between the case of two interfaces and a single interface is that there are more closed orbits corresponding to more frequencies of the oscillations. This study sheds a new light on the spontaneous emission process for atoms in the presence of environments.