Integrated thermal emission microchip based on meta-cavity array.

Microscale infrared thermal emitters are highly demanded in a variety of applications such as micro-molecular thermal sensing and micro-thermal imaging. In this paper, we propose a micro-meta-cavity array through combining nanohole metasurfaces and Fabry-Pérot (FP) cavity. Based on this design, integrated multiband micro-thermal emitters covering 7 - 9 μm and 10 - 14 μm wavelength ranges with high spatial resolution near wavelength scale has been theoretically and experimentally demonstrated simultaneously, providing the possibility for microscale infrared sources. In addition, narrow thermal emission bandwidth is enabled by the interaction between the resonant modes of metasurface and the FP cavity mode in meta-cavity. The emission features of each meta-cavity are investigated and analyzed through thermal imaging. Furthermore, polarization, wavelength and spatial multiplexing thermal emission with high spatial resolution is also experimentally demonstrated utilizing nanohole patterns. We anticipate that this thermal emission microchip can be possibly employed in micro-molecular sensing and micro-thermal imaging in the future.