Dynamic Thermal Emission Control Based on Ultrathin Plasmonic Metamaterials Including Phase‐Changing Material GST

Abstract

Dynamic thermal emission control has attracted growing interest in a broad range of fields, including radiative cooling, thermophotovoltaics and adaptive camouflage. Previous demonstrations of dynamic thermal emission control present disadvantages of either large thickness or requiring sustained electrical or thermal excitations. In this paper, an ultrathin (∼0.023λ, λ is the emission peak wavelength) metal‐insulator‐metal plasmonic metamaterial‐based zero‐static‐power mid‐infrared thermal emitter incorporating phase‐changing material GST is experimentally demonstrated to dynamically control the thermal emission. The electromagnetic modes can be continuously tuned through the intermediate phases determined by controlling the temperature. A typical resonance mode, which involves the coupling between the high‐order magnetic resonance and anti‐reflection resonance, shifts from 6.51 to 9.33 μm while GST is tuned from amorphous to crystalline phase. This demonstration will pave the way towards the dynamical thermal emission control in both the fundamental science field and a number of energy‐harvesting applications.

Hierarchical Metamaterials for Multispectral Camouflage of Infrared and Microwaves

“…In principle, perfect absorption is achieved in an MDM structure by: 1) obtaining zero reflection by matching the impedance; 2) obtaining zero transmission by using the metal ground, and 3) obtaining perfect absorption by maximizing the losses. By tailoring the effective permittivity and permeability of subwavelength artificial structures over various spectral ranges, the spectrum of an MPA has been expanded from microwave wavelengths [20] all the way up to the IR, [21,22] visible light domains, [19] and multispectral range. [23] Operation over a broad radiation spectrum is valuable for state-of-the-art military guidance systems, which have homing systems that use emitted IR and reflected microwave signals to search for and track military targets over detection distances.…”

Active analog tuning of the phase of light in the visible regime by bismuth-based metamaterials

“…In contrast with VO2, the crystalline phase formed upon heating above 250ºC remains upon cooling. [8][9][10][11][12][13][14][15][16][17][18][19] However, returning to the original amorphous phase requires energetic processes such as melt-quenching near 600ºC or irradiation with electrons or light pulses. [8,10,12,15,16,18] Interestingly, although tuning based on a phase transition conveys a binary picture involving an "off" and an "on" state, multilevel and even analog tuning of the optical properties of PCMs were recently reported.…”

“…[8,10,12,15,16,18] Interestingly, although tuning based on a phase transition conveys a binary picture involving an "off" and an "on" state, multilevel and even analog tuning of the optical properties of PCMs were recently reported. [4,6,7,13,14,[16][17][18] This opens the way to photonic devices with outstanding features such as color that can be tuned actively and in an analog manner, or optical data storage with enhanced information density. The fine tuning reported in these works was made possible by triggering the phase transition of a controlled volume fraction of the material, to achieve a controlled proportion of both phases.…”

Near‐Infrared Super‐Absorbing All‐Dielectric Metasurface Based on Single‐Layer Germanium Nanostructures

“…So far, strategies for breaking the 50% absorption limit in the visible and infrared region are mainly based on metal‐dielectric schemes. These strategies include metal–insulator–metal plasmonic absorbers, dielectric‐on‐metal absorbers, film stacks‐based Fabry‐Perot cavity absorbers, etc. However, for these designs with the aid of metals, a significant portion of absorption takes place in metals, where heat instead of photocarriers is generated.…”