A dynamically temperature tunable broadband infrared absorber with cross square nanocolumn arrays

Ultra-broadband and tunable infrared absorber based on VO2 hybrid multi-layer nanostructure

“…A higher figure of merit (FOM) of the absorber 𝐹𝐹𝐹𝐹𝐹𝐹 = 𝐴𝐴 ̄× 𝛥𝛥𝛥𝛥 can be achieved in this work, where 𝐴𝐴 ̄ and Δ𝛥𝛥 are average absorptivity and operation bandwidth [41]. Compared with our previous work [42], the new structural design greatly widens the operation bandwidth of the absorber while maintaining an ultra-high absorption rate. It is reasonable to evaluate the tunability of the absorber by the product of the maximum absorption modulation depth ℎ(𝜆𝜆) and the operation bandwidth Δ𝛥𝛥 as a reference value.…”

Review of Broadband Metamaterial Absorbers: From Principles, Design Strategies, and Tunable Properties to Functional Applications

“…By integrating VO 2 /SiO 2 /VO 2 nanopillar arrays on Al 2 O 3 substrates with W/VO 2 /W nanopillar arrays on W substrates, an IR BMA with dynamically tuned absorbance was presented by thermally induced VO 2 phase transition. [ 479 ] Moreover, an IR BMA consisting of VO 2 multilayer films was also suggested, [ 480 ] exhibits a tunable absorption feature in the wavelength ranges of 5–9.3 µm and 3.9–8.2 µm, with modulation depths up to 88% by thermally triggered phase transitions of VO 2 .…”

“…VO 2 , as one of the most popular phase change active materials in the field of metamaterials or super interfaces in recent years, can dynamically switch between metal and insulator properties that can be inseparable from the conductivity through temperature changes, providing a basis for thermal tuning BMAs. [93,96,[476][477][478][479][480] Importantly, VO 2 has two outstanding advantages: [93,96,[476][477][478][479][480] First, the conductivity of VO 2 is capable of multiple orders of magnitude variation; Second, its phase transition is reversible that could offer a new path to adjust the spectral properties of metamaterials. Therefore, this section first presents the dynamic modulation of VO 2 -based BMAs and then discusses BMAs with thermally tunable properties based on GST, [481][482][483][484][485][486][487][488][489] indium antimonide (InSb), [490,491] strontium titanate (STO), [492,493] nanocomposites, [494] and water.…”

Broadband near unity absorption meta-structure for solar thermophotovoltaic systems and optical window applications

“…The described meta-structure exhibits oblique incidence angle insensitivity up to 45 degrees with an average absorption of 92% from 400 to 2400 nm. Zhou et al 35 presented a meta-structure made with a thin metal–insulator–metal (MIM) stack, which comprises a grid of cross-shaped titanium (Ti) resonators, a silica dielectric spacer, and an opaque titanium slab. Here, the described absorber achieved a mean absorption of 93.8% over the 400–2500 nm wavelength range.…”

“…In addition to solar applications, researchers are proposing meta-structure absorbers for light-to-heat conversion, and photo-thermal and photodetector applications. Zhao et al 35 suggested a broad-band infrared absorber using cross-square nanocolumn arrays for thermal photoelectric devices, where the average absorption was found to be 95.5%. Zhang et al 36 suggested a four-layer periodic meta-structure with ultra wide-angle and polarization-insensitive properties for visible spectrum light-to-heat conversion applications.…”