مهدی سلطانی

In this thesis the spontaneous emission rate of an atom in the vicinity of a semi infinite dielectric medium is computed.Using Fermi golden rule, an expression for spontaneous emission rate between two eigenstate of atom (with definite electric dipole moment) is introduced since the expression is interms of electric field operator correlation Function, It can be related to the imaginary part OR vector potential Green Function through the fluctuation dissipation theorem and kubo’s formula. Finally computing the Green Function of the semi infinite dielectric slab, the spontaneous emission rate is evaluated. In this method the spontaneous emission rate is computed without using the explicit form of the electric field operator which is the most important point in this approach.