Light emitting device with a photonic crystal

摘要

A light emitting device includes a photonic crystal having a periodic pattern of elements exhibiting a spectrum of electromagnetic modes that includes guided modes of frequencies below a predetermined cutoff frequency, and radiation modes of frequencies below and above the cutoff frequency. A radiation source is associated with the photonic crystal. Each of the elements is covered by a reflective layer so as to introduce at least an omnidirectional photonic band gap between the guided modes and so as to permit coupling of the radiation to the radiation modes rather than to the guided modes.