Surface-plasmon field controlled quantum-dot light absorption and spontaneous emission

Abstract

The possibility for controlling both the probe-field optical gain and absorption switching as well as photon conversion by a surface-plasmon-polariton near field is explored for a quantum dot located above a metal surface. In contrast to the linear response in the weak-coupling regime, the obtained spectra could show an induced optical gain and a triply-split spontaneous emission peak resulting from the interference between the surface-plasmon field and the probe or self-emitted light field in such a strongly-coupled nonlinear system.

Controlling quantum-dot light absorption and emission by a surface-plasmon field

“…Part of the brief description for our self-consistent formalism was reported earlier. [16] In order to let readers follow up easily with the details of our model and formalism, we present here the full derivation of the Maxwell-Bloch numerical approach for an SPP field coupled to a photo-excited e-h plasma in the quantum dot.…”

“…using bare electron states or linear response theory, [5] become inadequate for describing both field and electron dynamics in this system. The presence of an induced polarization, regarded as a source term to the Maxwell equations, [15,16] from photo-excited electrons makes it impossible for us to solve the field equations by simply using finite-element analysis [17] or finite-difference-time-domain methods [18]. Although the semiconductor-Bloch equations [19] and density-matrix equations [5,20], derived from manybody theory, are able to accurately capture the nonlinear optical response of electrons, the inclusion of pair scattering effects on both energy relaxation and optical dephasing precludes an analytical approach for seeking solution of these equations.…”