Infrared Perfect Absorbers and Thermal Emitters with Tunable and Ultrabroad Bandwidth Based on Metamaterial Cavities

CBET-1402743杨可再生能源大大减少了传统化石能源的消耗，在减少温室气体方面发挥着重要作用。特别地，热光伏（TPV）能量转换系统可以将热能转换成电，并且这些系统可以方便地安装在许多工业环境中，以收集来自发动机、马达或其他高温热源的废热。提高TPV系统转换效率的一个主要挑战是在设计的频率范围内实现具有接近统一吸收率的红外吸收器和具有高发射率的热发射器。光学超材料是一种具有特殊性能的人工结构材料，可以用来实现高性能的红外吸收和热发射。在该提案中，设计并演示了一种新型的三维超材料红外完美吸收器和具有先进性能的热发射器，以解决TPV系统的主要挑战。这项研究也将有利于太阳能收集，热探测和红外传感等其他应用。拟议的研究将通过暑期研究学院项目和少数民族工程项目介绍为高中生开展外展活动来加强。该项目还包括培训和指导研究生和本科生的教育活动，特别是代表性不足的少数民族和妇女。电磁波能量转换和传输是可再生能源发电的一个令人兴奋的研究领域，包括光伏（PV）和热光伏（TPV）能量转换。为了大幅度提高TPV系统的转换效率，需要设计宽带红外完全吸收器和选择性可调谐波段热发射器，以适应TPV组件所需的吸收或发射光谱特性。开发TPV的一项新技术是光学超材料。虽然平面超材料已经被用来设计理想的红外吸收体，但它们仍然存在带宽窄、偏振依赖性和入射角受限等缺点，这些缺点严重限制了TPV器件的性能。本项目的目标是研究和展示一种新型的三维超材料红外理想吸收体和热发射体，该超材料红外理想吸收体和热发射体基于超材料腔体，具有可调谐和超宽带宽、偏振无关和宽入射角等优点，以解决理想吸收体的研究挑战。本文将通过理论分析和数值模拟对超材料腔的光学特性进行详细研究。光吸收引起的热产生和温度变化的超材料吸收器内也将被强调。优化的超材料腔将被制造，并将展示具有先进性能的红外完美吸收器和热发射器。

CBET-1402743YangRenewable energy dramatically reduces the consumption of conventional fossil energy and plays an important role in the reduction of greenhouse gases. In particular, thermophotovoltaic (TPV) energy conversion systems can convert thermal energy into electricity and these systems can be installed conveniently in many industrial environments to collect waste heat from engines, motors, or other high temperature sources of heat. A major challenge in increasing the conversion efficiency of TPV systems is to realize infrared absorbers with near-unity absorptivity and thermal emitters with high emissivity in the designed frequency range. Optical metamaterials are artificially structured materials to realize extraordinary properties and these materials can be used to realize high-performance infrared absorbers and thermal emitters. In this proposal, a new type of three-dimensional metamaterial infrared perfect absorbers and thermal emitters with advanced properties are designed and demonstrated to address the major challenge of TPV systems. This research will also benefit other applications in solar energy harvesting, thermal detection, and infrared sensing. The proposed research will be enhanced by outreach activities for high school students through summer research academy program and minority introduction to engineering program. The project also includes educational activities for training and mentoring graduate and undergraduate students especially underrepresented minorities and women.Energy conversion and transport with electromagnetic waves is an exciting research area for renewable energy generation, including photovoltaic (PV) and thermophotovoltaic (TPV) energy conversion. In order to greatly enhance the conversion efficiency of TPV systems, broadband infrared perfect absorbers and selective tunable-band thermal emitters need to be designed to fit the required absorption or emission spectrum characteristics of TPV components. One new technology for developing TPVs is optical metamaterials. Although planar metamaterials have been studied to design infrared perfect absorbers, they still suffer disadvantages of narrow bandwidth, polarization dependence and limited incident angle, which limit the TPV device performance significantly. The goal of this proposal is to study and demonstrate a new type of three-dimensional metamaterial infrared perfect absorbers and thermal emitters based on metamaterial cavities, with the advantages of tunable and ultrabroad bandwidth, polarization independence, and wide incident angle, in order to address the research challenges in perfect absorbers. The optical properties of metamaterial cavities will be investigated in detail with theoretical analysis and numerical simulations. The light absorption induced heat generation and temperature variation inside the metamaterial absorbers will also be emphasized. The optimized metamaterial cavities will be fabricated and infrared perfect absorbers and thermal emitters with advanced properties will be demonstrated.