Tailoring emission spectra by using microcavities

Abstract

We present a theoretical model to describe emission spectrum of an emitter in a micro-cavity. Our model proposes that the spectrum in a metal micro-cavity depends on the product of the emission spectrum in free space and the local density of states (LDOS) in the cavity which the emitter is placed in. Since Purcell effect can enhance LDOS of a micro-cavity, the emission intensity of an emitter is directly proportional to LDOS depending on the geometry of microcavity. Thus, the model predicts that the spectrum of an emitter can be modified as a narrow spectrum in microcavity possessing sharp LDOS spectrum, also can be modified as broadband spectrum with broadband LDOS spectrum. Finite-difference time-domain (FDTD) numerical simulations support our prediction. Keywords: Emission spectrum, Emitter, Microcavity, Local density of states