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We present a class of inverse-designed, aperiodic multilayer graphene-based perfect absorbers operating in the mid-infrared spectrum (3–5 μm), a range vital for atmospheric transparency and advanced sensing. Our design leverages a fixed material sequence—graphene, PPSU dielectric spacers, and PbSe layers on a gold substrate—while achieving precise spectral tunability solely through layer thickness variation, enabling absorption peak control in 0.25 μm steps without any change in material composition. This physical tunability allows scalable fabrication of wavelength-specific devices using a single manufacturing process. We further demonstrate electrical switchability by dynamically modulating graphene’s chemical potential (µc from 0 eV to 1 eV), enabling absorption amplitude control and wavelength redshifting without structural alteration. The proposed absorber achieves > 99.9% efficiency using only five graphene layers in a compact ~ 2 μm stack, offering significant advantages in size, weight, power, and cost. Our hybrid micro-genetic inverse design algorithm enables this performance while preserving > 90% absorption at incidence angles up to 52°, supporting broad angular robustness. Extensive simulation and field distribution analyses confirm the role of plasmonic confinement and impedance matching. Additionally, we validate the design’s fabrication tolerance and benchmark its performance against recent state-of-the-art absorbers. By combining advanced inverse design with nanophotonic structures, our work advances the field of mid-infrared absorbers, providing a scalable and efficient platform for next-generation optical devices.
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High-efficiency and ultrabroadband flexible absorbers based on transversely symmetrical multi-layer structures
Two ultrabroadband and omnidirectional perfect absorbers based on transversely symmetrical multilayer structures are presented, which are achieved by four absorptive metal chromium (Cr) layers, antireflection coatings, and the substrates, glass and PMMA, in the middle. At the initial step, the proposed planar structure shows an average absorption of ∼93% over the visible (VIS) and near-infrared range from 400 to 2500 nm and 98% in the VIS range. The optimum flat is optically characterized by the transfer matrix method and local metal-insulator-metal resonance under illumination with transverse-electric and transverse-magnetic polarization waves. The multilayer materials, which are deposited on an intermediate substrate by e-beam evaporation, outperform the previously reported absorbers in the fabrication process and exhibit a great angular tolerance of up to 60°. Afterward, we present a novel symmetrical flexible absorber with the PMMA substrate, which shows not only perfect absorption but also the effect of stress equilibrium. The presented devices are expected to pave the way for practical use of solar-thermal energy harvesting.
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- Award ID(s):
- 1634832
- PAR ID:
- 10596889
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- AIP Advances
- Volume:
- 9
- Issue:
- 11
- ISSN:
- 2158-3226
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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