Mid-infrared thermal detectors have very important applications in the aerospace and military fields. However, due to the low heat transfer efficiency and slow response time, their application has been greatly restricted. Here, we theoretically demonstrate a dual-band perfect absorber for a mid-infrared detector based on a dielectric metal metasurface, and the optical and thermal properties are analyzed in detail. Simulation results show that the two narrow absorption peaks, corresponding to the absorption value of 97.5% at $\lambda =6.142\mathrm{\mu m}$ with ${\lambda }_{\mathrm{FWHM}}\approx 40\mathrm{nm}$ and 99.7% at $\lambda =7.795\mathrm{\mu m}$ with ${\lambda }_{\mathrm{FWHM}}\approx 80\mathrm{nm}$, respectively, are achieved, and their different dependences on the structural parameters have been studied. A thermal detector at room temperature with total response time within 1.3 ms for dual-band and 0.4 ms for single-band is realized when the incident light flux is $1.0\mathrm{W}/{\mathrm{cm}}^2$ for an average temperature increase of $\mathrm{\Delta }T\approx 1.0\mathrm{K}$. Our study offers a promising approach for designing a narrowband mid-infrared perfect absorber and a high-performance photodetector in nano-integrated photonics.

中文翻译：

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基于介电金属超表面的中红外光电探测器双波段完美吸收体

中红外热探测器在航空航天和军事领域具有非常重要的应用。但是，由于传热效率低和响应时间慢，其应用受到很大限制。在这里，我们从理论上论证了基于介电金属超表面的用于中红外探测器的双频完美吸收体，并对光学和热学性质进行了详细分析。仿真结果表明，两个窄的吸收峰，对应于97.5％的吸收值。$\lambda =6.142\mathrm{微米}$ 与 ${\lambda }_{\mathrm{半高宽}}\approx 40\mathrm{纳米}$ 和99.7％ $\lambda =7.795\mathrm{微米}$ 与 ${\lambda }_{\mathrm{半高宽}}\approx 80\mathrm{纳米}$分别实现，并研究了它们对结构参数的不同依赖性。当入射光通量为时，可实现一个室温下的热探测器，双波段的总响应时间在1.3 ms之内，单波段的总响应时间在0.4 ms之内。$1.0\mathrm{w\; ^}/{\mathrm{厘米}}^2$ 平均温度上升 $\mathrm{\Delta }Ť\approx 1.0\mathrm{ķ}$。我们的研究为纳米集成光子学中窄带中红外完美吸收体和高性能光电探测器的设计提供了一种有希望的方法。