Monochromatic polarized coherent emitter enhanced by surface plasmons and a cavity resonance

In this paper we propose and analyze a design of multilayer nanostructure that could be used as a tunable monochromatic polarized thermal emitter in the visible region for any direction with large temporal coherence and spatial coherence extending into the far field. The thermal emitter has a cavity that is surrounded by a thin silver grating having converging-diverging channel on one side and by a one-dimensional (1D) photonic crystal (PhC) on the other side. The large coherence length is achieved by making use of the coherence properties of the surface waves. Due to the nature of surface waves the new multilayer structure can attain the spectral and directional control of thermal radiation with only $p$ polarization. Finite element method was used for analyzing the emission properties of the thermal emitter. The resonance condition inside the cavity is extremely sensitive to the wavelength, which would then lead to high emission in a very narrow wavelength band. Such simple 1D multilayer structure should be easy to fabricate and have applications in photonic circuits, thermophotovoltaics and potentially in energy efficient incandescent sources.