Broadband mid-infrared (MIR) light harvesting is critical for a wide range of applications, including thermophotovoltaic conversion, thermal sensing and imaging, infrared camouflage and anti-counterfeiting technologies. In this study, we present the design and experimental validation of a deep-subwavelength broadband MIR light-harvesting metacoating (MMC), optimized through a genetic algorithm (GA)-based inverse design approach. The strength of this approach lies in its ability to automate and optimize the complex multilayer structure, encompassing both material selection and structural thickness, thereby achieving unparalleled performance in broadband MIR light absorption, with an average absorbance of approximately 0.85 across the 3–13 μm spectral range and nearly perfect absorption within the 4–12 μm range. This exceptional performance is attributed to strong electromagnetic localization within its multilayer configuration, facilitating efficient energy dissipation via high-loss materials such as bismuth and titanium. Notably, the MMC exhibits robust performance with respect to angle and polarization variations, maintaining high absorbance even at incident angles up to 70°. Its large-area fabrication capabilities and compatibility with various substrates further enhance its practical applicability. Two specific applications, long-wavelength infrared camouflage and anti-counterfeiting, highlight its potential for real-world deployment. In these applications, the MMC seamlessly integrates into high-emission environments and enables the modulation of patterned infrared emission, providing a lithography-free, cost-effective solution compared to conventional methods relying on artificially engineered structures. This work underscores the versatility of the developed MMC for a diverse array of MIR applications, ranging from camouflage technologies to advanced security measures.

中文翻译：

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用于红外伪装和防伪的亚波长宽带光收集超涂层，由逆向设计赋能


宽带中红外 （MIR） 光收集对于广泛的应用至关重要，包括热光伏转换、热传感和成像、红外伪装和防伪技术。在这项研究中，我们提出了深亚波长宽带 MIR 光捕获超涂层 （MMC） 的设计和实验验证，该涂层通过基于遗传算法 （GA） 的逆向设计方法进行了优化。这种方法的优势在于它能够自动化和优化复杂的多层结构，包括材料选择和结构厚度，从而在宽带 MIR 光吸收方面实现无与伦比的性能，在 3-13 μm 光谱范围内的平均吸光度约为 0.85，在 4-12 μm 范围内几乎完美的吸收。这种卓越的性能归因于其多层配置中的强大电磁局部化，有助于通过铋和钛等高损耗材料实现高效能量耗散。值得注意的是，MMC 在角度和极化变化方面表现出稳健的性能，即使在高达 70° 的入射角下也能保持高吸光度。其大面积制造能力和与各种基材的兼容性进一步增强了其实际适用性。长波长红外伪装和防伪这两个特定应用凸显了它在实际应用中的潜力。在这些应用中，MMC 无缝集成到高发射环境中，并支持调制图案化红外发射，与依赖人工工程结构的传统方法相比，提供了一种无需光刻且经济高效的解决方案。 这项工作强调了开发的 MMC 的多功能性，适用于各种 MIR 应用，从伪装技术到高级安全措施。