文摘
The origins of the directivity and frequency selectivity of radiating sources embedded in photonic microcavities are examined. We start from a quasi-1D approach for unbounded systems which, by analogy with resonant tunnelling processes in semiconductor superlattices, gives us the intrinsic relationships between angular and frequency properties of the radiating system. The cavity design in a three-dimensional configuration and the consequences of the openness of the system on the radiation properties are addressed. It is shown that the evanescence properties of the electromagnetic waves within cavity walls associated with a unitary transmission induced by a resonant defect mode of a symmetric structure are key parameters in the design of a highly directive radiating system.