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常规化石能源的消耗，在减少温室气体排放方面发挥着重要作用。特别是，热光伏(TPV)能量转换系统可以将热能转换为电能，这些系统可以方便地安装在许多工业环境中，以收集发动机、发动机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单位吸收率的红外吸收体和具有高发射率的热发射体。光学超材料是一种人工构造的材料，可以实现优异的性能，可以用来实现高性能的红外吸收和热发射。在这个方案中，设计并展示了一种新型的具有先进性能的三维超材料红外完美吸收和热发射器，以应对TPV系统的主要挑战。这项研究还将有助于太阳能收集、热探测和红外传感等领域的其他应用。建议的研究将通过暑期研究学院计划和少数族裔工程介绍计划针对高中生的外展活动来加强。该项目还包括培训和指导研究生和本科生的教育活动，特别是代表人数不足的少数族裔和妇女。利用电磁波进行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)能源转换。为了大大提高TPV系统的转换效率，需要设计适合TPV组件所要求的吸收或发射光谱特性的宽带红外完美吸收体和选择性可调谐波段热发射体。开发热塑性弹性体的一项新技术是光学超材料。虽然人们已经研究了平面超材料来设计理想的红外吸收材料，但它们仍然存在带宽窄、偏振相关、入射角度有限等缺点，这严重限制了TPV器件的性能。该方案的目标是研究和展示一种新型的基于超材料腔的三维超材料红外完美吸收器和热发射器，具有可调谐和超宽带带宽、偏振无关和大入射角的优点，以应对完美吸收器的研究挑战。通过理论分析和数值模拟，详细研究了超材料腔的光学性质。还将强调光吸收引起的热产生和超材料吸收体内的温度变化。优化的超材料腔体将被制造出来，并将展示具有先进性能的红外完美吸收体和热发射体。

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.