Siegel Joel, Kim Shinho, Fortman Margaret, Wan Chenghao, Kats Mikhail A, Hon Philip W C, Sweatlock Luke, Jang Min Seok, Brar Victor Watson
Department of Physics, University of Wisconsin-Madison, Madison, WI, USA.
School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea.
Nat Commun. 2024 Apr 20;15(1):3376. doi: 10.1038/s41467-024-47229-0.
We theoretically describe and experimentally demonstrate a graphene-integrated metasurface structure that enables electrically-tunable directional control of thermal emission. This device consists of a dielectric spacer that acts as a Fabry-Perot resonator supporting long-range delocalized modes bounded on one side by an electrostatically tunable metal-graphene metasurface. By varying the Fermi level of the graphene, the accumulated phase of the Fabry-Perot mode is shifted, which changes the direction of absorption and emission at a fixed frequency. We directly measure the frequency- and angle-dependent emissivity of the thermal emission from a fabricated device heated to 250 °C. Our results show that electrostatic control allows the thermal emission at 6.61 μm to be continuously steered over 16, with a peak emissivity maintained above 0.9. We analyze the dynamic behavior of the thermal emission steerer theoretically using a Fano interference model, and use the model to design optimized thermal steerer structures.
我们从理论上描述并通过实验证明了一种集成石墨烯的超表面结构，该结构能够实现热发射的电可调定向控制。该器件由一个介电间隔层组成，该间隔层充当法布里 - 珀罗谐振器，支持由静电可调金属 - 石墨烯超表面在一侧界定的长程离域模式。通过改变石墨烯的费米能级，法布里 - 珀罗模式的累积相位发生偏移，这会改变固定频率下吸收和发射的方向。我们直接测量了加热到250°C的制造器件热发射的频率和角度相关发射率。我们的结果表明，静电控制允许6.61μm处的热发射在16°范围内连续转向，峰值发射率保持在0.9以上。我们使用法诺干涉模型从理论上分析了热发射转向器的动态行为，并使用该模型设计优化的热转向器结构。
