Nishijima Yoshiaki, To Naoki, Balčytis Armandas, Juodkazis Saulius
Opt Express. 2022 Jan 31;30(3):4058-4070. doi: 10.1364/OE.447885.
Detailed spectral analysis of radiation absorption and scattering behaviors of metasurfaces was carried out via finite-difference time-domain (FDTD) photonic simulations. It revealed that, for typical metal-insulator-metal (MIM) nanodisc metasurfaces, absorbance and scattering cross-sections exhibit a ratio of σ/σ = 1 at the absorption peak spectral position. This relationship was likewise found to limit the attainable photo-thermal conversion efficiency in experimental and application contexts. By increasing the absorption due to optical materials, such as Cr metal nano-films typically used as an adhesion layer, it is possible to control the total absorption efficiency η = σ/σ and to make it the dominant extinction mechanism. This guided the design of MIM metasurfaces tailored for near-perfect-absorption and emission of thermal radiation. We present the fabrication as well as the numerical and experimental spectral characterisation of such optical surfaces.
通过时域有限差分（FDTD）光子模拟对超表面的辐射吸收和散射行为进行了详细的光谱分析。结果表明，对于典型的金属-绝缘体-金属（MIM）纳米盘超表面，在吸收峰光谱位置处，吸光度与散射截面的比值为σ/σ = 1。同样发现，这种关系在实验和应用环境中限制了可实现的光热转换效率。通过增加光学材料（如通常用作粘附层的Cr金属纳米膜）的吸收，可以控制总吸收效率η = σ/σ，并使其成为主要的消光机制。这为设计用于近乎完美吸收和发射热辐射的MIM超表面提供了指导。我们展示了这种光学表面的制造以及数值和实验光谱表征。
