Transformation Laplacian metamaterials: recent advances in manipulating thermal and dc fields

Abstract

The full control of single or even multiple physical fields has attracted intensive research attention in the past decade, thanks to the development of metamaterials and transformation optics. Significant progress has been made in vector fields (e.g., optics, electromagnetics, and acoustics), leading to a host of strikingly functional metamaterials, such as invisibility cloaks, illusion devices, concentrators, and rotators. However, metamaterials in vector fields, designed through coordinate transformation of Maxwell's equations, usually require extreme parameters and impose challenges on the actual realization. In this context, metamaterials in scalar fields (e.g., thermal and dc fields), which are mostly governed by the Laplace equation, lead to more plausible and facile implementations, since there are native insulators and excellent conductors (serving as two extreme cases). This paper therefore is particularly dedicated to reviewing the most recent advances in Laplacian metamaterials in manipulating thermal (both transient and steady states) and dc fields, separately and (or) simultaneously. We focus on the theory, design, and realization of thermal/dc functional metamaterials that can be used to control heat flux and electric current at will. We also provide an outlook toward the challenges and future directions in this fascinating area.

Transformation Optics: From Classic Theory and Applications to its New Branches

“…Many devices designed by TO have been extended to other physical fields for different applications (see some recent reviews for details, Refs. [] and []). Multiphysical devices that control two different physical fields at the same time in a predesigned manner can also be designed using a coordinate transformation method and have been experimentally demonstrated …”

A Brief Review on Thermal Metamaterials for Cloaking and Heat Flux Manipulation

“…In this review, we focus on the advances in the design of thermal metamaterials and devices, which have been demonstrated to exhibit unprecedented properties. We left a side deeply discussions regarding theories related to metamaterials design, which are fully detailed and explained in other reviews . In contrast, this study is oriented to summarize significant aspects regarding the current level of development, potentialities, and prospects in such a topic.…”

“…We left a side deeply discussions regarding theories related to metamaterials design, which are fully detailed and explained in other reviews. [17][18][19][20] In contrast, this study is oriented to summarize significant aspects regarding the current level of development, potentialities, and prospects in such a topic. We start with applications for invisibility and camouflage, then we continue with energyconcentration devices and with examples of thermal inverters that exhibit extreme heat flux manipulation capabilities.…”

Invisibility problem in acoustics, electromagnetism and heat transfer. Inverse design method

“…Then the main results of the electromagnetic cloaking theory were expanded to an acoustic cloaking [6] and to cloaking static (magnetic, electric and thermal) fields (see, e.g., [7,8,9]). Papers [10,11] are devoted to studying invisibility problems in X-ray tomography.…”