Quantum Optics of Low-Dimensional Electrons in Layered Structures

Abstract

A two-level atom of excitation energy E outside a metallic half-space can couple strongly to the surface plasmons if E/ħ is closely tuned to the limiting surface plasmon frequency of the metal¹. This physical situation is the simplest ‘cavity QED’ problem² in which entangled states (linear combinations of atomic states and single surface plasmonpolariton states) can be realised, but it is, in fact, more general than the example might suggest. In low dimensional structures³ the excitation energy E could belong to an impurity atom, or be associated with a quantum well (2D) or a quantum wire (1D). A quantum dot (0D) can be regarded as the macroscopic analogue of an atom. Whenever E matches any one of a number of possible modes supported by the layered structure the spectrum of the scattered light in a light scattering experiment should exhibit a doublet in the frequency region of the resonance.