Characterization of Near-Field Thermal Radiative Properties of Man-Made Materials

在非常小（纳米）尺度上设计的人造材料已被提议用于热辐射应用。这些材料的辐射特性已经用精确或近似的方法进行了理论研究。然而，这些理论预测从未得到实验验证。该项目的目的是通过实验证明，利用人造材料，如超材料、光栅和光子晶体，可以实现新的热辐射特性。设计热辐射的能力将导致能量转换和守恒方面的技术突破，并将显著加速热辐射应用的发展，如利用纳米间隙热光伏器件进行废热回收和纳米尺度的热管理。这将有利于社会减少化石燃料的消耗，从而节省我们有限的能源资源和环境。该项目的目的是测试近场热辐射光谱可以使用人造材料在亚波长尺度上进行调谐的假设。这一假设将通过测量各种人造结构的近场热发射光谱来验证。测量的光谱将与理论预测进行比较，并将用于验证和调整理论模型。本研究将在多个方面促进纳米尺度辐射传热领域的知识和技术进步。本文将通过实验证明，利用人造材料可以实现可调谐的近场热辐射。建立了一种可靠的近场热发射光谱测量技术。该项目将为人造材料的近场热辐射机理提供物理见解，并将有助于建立理论模型，加速具有新型辐射特性的材料的设计和发现。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Man-made materials that are engineered at the very small (nanometer) scale have been proposed for thermal radiation applications. The radiative properties of these materials have been studied theoretically using exact or approximate methods. However, these theoretical predictions have never been experimentally verified. The objective of this project is to experimentally demonstrate that novel thermal radiative properties can be achieved using man-made materials such as metamaterials, gratings, and photonic crystals. The ability to engineer thermal radiation will lead to technological breakthroughs in energy conversion and conservation, and will significantly accelerate the development of thermal radiation applications such as waste heat recovery using nano-gap thermophotovoltaic devices and thermal management at the nanoscale. This will benefit the society by reducing consumption of fossil fuels and thus conserving our limited energy resources and the environment.The objective of this project is to test the hypothesis that the spectrum of near-field thermal radiation can be tuned using man-made materials that are engineered at the sub-wavelength scale. This hypothesis will be tested by measuring the spectrum of near-field thermal emission from a variety of man-made structures. The measured spectra will be compared with theoretical predictions, and they will be used for validating and tuning the theoretical models. This research will contribute to the advancement of knowledge and technology in the field of nanoscale radiative heat transfer in several ways. It will be experimentally demonstrated that tunable near-field thermal radiation can be achieved using man-made materials. A robust technique will be established for measuring the spectrum of near-field thermal emission. This project will provide physical insight into the mechanisms of near-field thermal emission by man-made materials, and it will help to establish theoretical models that accelerate design and discovery of materials with novel radiative properties.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.