Yosuke Ueba

The spectral control of thermal radiation is demonstrated using isolated and connected split-ring resonators (SRR) as plasmonic metasurface. Thermally excited plasmonic resonant modes in a SRR are found to enhance thermal radiation at specific wavelengths even in connected SRRs. Since the thickness of the metasurface is significantly small compared to the wavelength, these devices have low heat capacity, resulting in high efficiency for energy conversion. Metafilament is a promising candidate for extremely thin film thermal emitter for wide range of the frequency from infrared to visible.

This paper theoretically describes coupling mechanism between spoof surface plasmon (SSP) and radiative field. We calculate absorbance of periodic microcavity array using exact Rigorous Couped-Wave Analysis (RCWA) method and discuss the coupling condition of SSP and incident beams. We derive angular dependence of emittance of thermal radiation and this results show quasi-vertical narrow-band thermal emission from the microcavity array.

In this Letter, the enhancement of thermal radiation in the terahertz region is presented theoretically by using the spoof surface plasmon mode on the microcavity array. We found that the terahertz wave is radiated selectively in a vertical direction. As a result, a quasi-monochromatic terahertz source can be created.