Ultrathin Three-Dimensional Thermal Cloak

Abstract

We report the first experimental realization of a three-dimensional thermal cloak shielding an air bubble in a bulk metal without disturbing the external conductive thermal flux. The cloak is made of a thin layer of homogeneous and isotropic material with specially designed three-dimensional manufacturing. The cloak's thickness is 100 μm while the cloaked air bubble has a diameter of 1 cm, achieving the ratio between dimensions of the cloak and the cloaked object 2 orders smaller than previous thermal cloaks, which were mainly realized in a two-dimensional geometry. This work can find applications in novel thermal devices in the three-dimensional physical space.

A transient thermal cloak experimentally realized through a rescaled diffusion equation with anisotropic thermal diffusivity

“…[1][2][3][4][5][6][7][8] The TO technique has also led to the creation of many other important EM devices with functionalities previously deemed impossible or unconceivable. [9][10][11] In general, this coordinate operation can be applied to different partial differential equations governing the behaviors of other physical phenomena such as thermal flux, [12][13][14][15][16][17][18][19][20][21][22][23] acoustic wave, [24][25][26][27] and matter or quantum [28][29][30] waves, demonstrating important scientific and application potentials.…”

Neutral shielding and cloaking of magnetic fields using isotropic media

“…This form occurs in many situations of physics and cloaking, including static thermal cloaks [38,39], direct current electric cloaks [40] and diffusive light cloaks [41]. We note that it is possible to derive analogous theoretical results for other canonical geometries, e.g., in spherical symmetry, following a similar methodology.…”

An elasto-mechanical unfeelability cloak made of pentamode metamaterials

“…Invisibility cloaks [4][5][6][7] and counterparts thereof are demonstrations of this progress. Cloaks have been demonstrated experimentally in electromagnetism at microwave 8 and at optical frequencies [9][10][11] , in airborne 12,13 and fluid-borne acoustics 14 , for fluid surface waves 15 , for electrical 16 and heat conduction [17][18][19] , as well as for flexural waves 20 in thin (quasi two-dimensional) elastic membranes. In three-dimensional (3D) solid mechanics, only unidirectional cloaking of stress waves in fibrous materials has been achieved 21 .…”

“…Next, a suitable structure is wrapped around these walls to make them and their interior appear identical to the surrounding. A similar core-shell approach has just recently been successfully used in thermal cloaking 18,19 . In this paper, we experimentally demonstrate an approximate core-shell elasto-mechanical cloak.…”