Spectroscopic assessment of a simple hybrid si-Au cell metasurface-based sensor in the mid-infrared domain

In this paper, we theoretically investigate the spectroscopic properties of a simple hybrid metasurface consisting in a periodic array of a Si-Au pattern in the mid-infrared spectral region. Our simulations show that our hybrid metasurface exhibits a strong spectral absorption band in the 5.5 mu m - 10 mu m region, by comparison to the typical Au-Au counterpart. A considerable improvement to the full-metal metasurface approach is that resonance in the mid-infrared is obtained with a pattern cell of just lambda/1.5 instead of the typical lambda/5 to lambda/8 requirement that occurs in full-metal structures, which relaxes the manufacturing constraints. To fully characterize the surface around resonance, we also performed wave propagation and thermal deposition investigations, the latter of which allows predictions of the shift in the resonance frequency caused by thermal dilation. The proposed metasurface constitutes a good candidate for use in mid-infrared and thermal detection devices, and benefits from the advantages of on-chip integration and scalability in THz generation-detection systems. (C) 2020 Elsevier Ltd. All rights reserved.