title: Near-field energy extraction with hyperbolic metamaterials.
abstract: Although blackbody radiation described by Planck's law is commonly regarded as the maximum of thermal radiation, thermal energy transfer in the near-field can exceed the blackbody limit due to the contribution from evanescent waves. Here, we demonstrate experimentally a broadband thermal energy extraction device based on hyperbolic metamaterials that can significantly enhance near-field thermal energy transfer. The thermal extractor made from hyperbolic metamaterials does not absorb or emit any radiation but serves as a transparent pipe guiding the radiative energy from the emitter. At the same gap between an emitter and an absorber, we observe that near-field thermal energy transfer with thermal extraction can be enhanced by around 1 order of magnitude, compared to the case without thermal extraction. The novel thermal extraction scheme has important practical implications in a variety of technologies, e.g., thermophotovoltaic energy conversion, radiative cooling, thermal infrared imaging, and heat assisted magnetic recording.
authors.affiliation: Department of Mechanical Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Jiawei
authors.initials: J
authors.lastname: Shi
authors.forename: Baoan
authors.initials: B
authors.lastname: Liu
authors.forename: Pengfei
authors.initials: P
authors.lastname: Li
authors.forename: Li Yen
authors.initials: LY
authors.lastname: Ng
authors.forename: Sheng
authors.initials: S
authors.lastname: Shen
keywords: Near field; energy transfer; hyperbolic metamaterials