Spectral Control of Thermal Radiation using Rectangular Micro-Cavities on Emitter-Surface for Thermophotovoltaic Generation of Electricity

Abstract

Spectral control of thermal radiation emitted from rectangular micro-cavities made on a metal surface was investigated through numerical simulation and experiment. In the numerical simulation, thermal radiation from solid surface was dealt as hemispherical emission from point sources, and the Maxwell's equations were solved using the cubic interpolated propagation method. It was demonstrated that spherical waves emitted from inside of a cavity were spectrally selected, and that the emittance could be increased around the wavelength corresponding to the standard mode of cavity resonance. Furthermore, in experiment using rectangular micro-cavities (0.5x0.5x0.5 µm 3 ) made periodically on Ni specularly-polished surface, spectral emittance was measured in the near-infrared region. The experimental results disclosed that the emissive power only in the range of shorter wavelength than 1.2 µm was increased by the micro-cavities that played a role of a wave guide to produce cutoff effect clearly.

Development of a Prototype Thermophotovoltaic Power Generation System Using Super-Adiabatic Combustion in Porous Quartz Glass

“…Recently, many selective emitters and infrared filters for spectral control have been investigated. (8)(9)(10) In addition to refinement for the component technology, a new comprehensive system model that realizes both spectral control of the emitted radiation and heat recovery of the combustion gas is required.…”

Near-field radiative heat transfer between two parallel SiO2 plates with and without microcavities

“…18,19 With these tests, we demonstrated a comparison of gapdependent radiative flux for cases with/without dielectric microcavities at the heat-transfer surfaces of the plates. Microcavities are formed on the precision-flatness SiO 2 substrates by a technique incorporating electron beam lithography and etching.…”

Spectral emittance measurements of micro/nanostructures in energy conversion: a review

“…Kirikae et al [65] constructed a setup consisting of a vacuum chamber, an infrared heat lamp, an IR spectrometer, and a sample holder made of amorphous graphite. Hanamura and Kameya [66] developed an emissiometry setup using CO 2 laser to heat the microstructured sample to near 1000 K.…”

“…However, 1D grating structures support MP resonances only for TM waves. When cavity resonances are excited, microcavities with 2D gratings boost the absorptance or emittance due to the enhanced density of states [62][63][64][65][66]. The resonance wavelengths of the cavity modes (for both TE and TM waves) must satisfy [62,81]…”

“…A variety of microcavities with different shapes and metal or coating materials have been fabricated and demonstrated with both broadband and narrowband emitters by many researchers [62,65,66,[110][111][112][113]. More details are summarized in Table 3.…”