title: Experimental demonstration of a bilayer thermal cloak.
abstract: Invisibility has attracted intensive research in various communities, e.g., optics, electromagnetics, acoustics, thermodynamics, dc, etc. However, many experimental demonstrations have only been achieved by virtue of simplified approaches due to the inhomogeneous and extreme parameters imposed by the transformation-optic method, and usually require a challenging realization with metamaterials. In this Letter, we demonstrate a bilayer thermal cloak made of bulk isotropic materials, and it has been validated as an exact cloak. We experimentally verified its ability to maintain the heat front and its heat protection capabilities in a 2D proof-of-concept experiment. The robustness of this scheme is validated in both 2D (including oblique heat front incidence) and 3D configurations. The proposed scheme may open a new avenue to control the diffusive heat flow in ways inconceivable with phonons, and also inspire new alternatives to the functionalities promised by transformation optics.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Republic of Singapore.
authors.forename: Tiancheng
authors.initials: T
authors.lastname: Han
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Republic of Singapore and Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117546, Republic of Singapore and NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore,Kent Ridge 119620, Republic of Singapore.
authors.forename: Xue
authors.initials: X
authors.lastname: Bai
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Republic of Singapore.
authors.forename: Dongliang
authors.initials: D
authors.lastname: Gao
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Republic of Singapore and NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore,Kent Ridge 119620, Republic of Singapore.
authors.forename: John T L
authors.initials: JT
authors.lastname: Thong
authors.affiliation: Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117546, Republic of Singapore and NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore,Kent Ridge 119620, Republic of Singapore and Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering, Tongji University, 200092 Shanghai, China.
authors.forename: Baowen
authors.initials: B
authors.lastname: Li
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Republic of Singapore and NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore,Kent Ridge 119620, Republic of Singapore.
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Qiu