Multiband terahertz absorbers are essential photonic components for responding to, manipulating, and modulating terahertz waves. In this work, improved electric split resonant ring arrays are used to demonstrate multiband terahertz wave absorption. The proposed design strategy is simple, practical, and significant. Experiments and simulations reveal perfect absorption at 0.918 THz and 1.575 THz for the transverse magnetic (TM) polarization and at 0.581, 1.294, and 1.556 THz for the transverse electric (TE) polarization. In addition, the weak resonant peaks that occurred in the experiments in both polarization states have been verified by the simulations. Furthermore, five concentration gradients of 2, 4-dichlorophenoxyacetic acid solutions and six concentration gradients of chlorpyrifos have been detected using the absorber. The lowest detectable concentration that could be monitored was 0.1 ppm. The absorption, intensity, and frequency shift values for the different solution concentrations at the resonant peaks were analyzed. The highest linear regression coefficients were 0.9862 and 0.9565 for the TE and TM polarizations, respectively. This multi-band absorber was demonstrated to be highly efficient in detecting pesticides for food safety applications.
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http://dx.doi.org/10.1364/OE.27.014133 | DOI Listing |
Sci Rep
December 2024
Department of Electronics, Carleton University, Ottawa, ON, K1S 5B6, Canada.
In this paper, we propose a novel structure of anisotropic graphene-based hyperbolic metamaterial (AGHMM) sandwiched as a defect between two one-dimensional photonic crystals (PCs) in the terahertz (THz) region. The proposed structure is numerically simulated and analyzed using the transfer matrix method, effective medium theory and three-dimensional finite-difference time-domain. The defect layer of AGHMM consists of graphene sheets separated by subwavelength dielectric spacers.
View Article and Find Full Text PDFNanophotonics
September 2024
Institute of Modern Optics, Nankai University, Tianjin, China.
Multi-resonant metasurfaces are of great significance in the applications of multi-band nanophotonics. Here, we propose a novel metasurface design scheme for simultaneously supporting quasi-bound states in continuum (QBIC) and other resonant modes, in which QBIC resonance is generated by mirror or rotational symmetry breaking in oligomers while other resonant modes can be simultaneously excited by rationally designing the shapes of meta-atoms within oligomers. As an example, the simultaneous excitation of QBIC and anapole modes are demonstrated in a dimer metasurface composed of asymmetric dumbbell-shaped apertures.
View Article and Find Full Text PDFMicromachines (Basel)
November 2024
School of Physics and Electronic-information Engineering, Hubei Engineering University, Xiaogan 432000, China.
In this article, we present a terahertz (THz) metamaterial absorber that blends two types of coordinated materials: Dirac semimetals and vanadium dioxide. Compared to other absorbers on the market, which are currently non-adjustable or have a single adjustment method, our absorber is superior because it has two coordinated modes with maximum adjustment ranges of 80.7% and 0.
View Article and Find Full Text PDFMulti-spectral imaging enhances the information diversity of the object with complex, expensive, and low integrated components. Here, we demonstrated an antenna-coupled microbolometric detector in complementary metal-oxide-semiconductor (CMOS) technology, utilizing SiO2 absorption and L-shaped fractal antenna to achieve multi-band detection from infrared (IR) to terahertz (THz). Experimental results demonstrate that the detector can achieve high sensitivity detection in both THz and IR bands, with the maximum detectivity of 5 (10 cm·Hz/W @305 GHz and 7 (10 cm·Hz/W @8.
View Article and Find Full Text PDFMaterials (Basel)
October 2024
Beijing Key Lab for Precision Optoelectronic Measurement Instrument and Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China.
Spectral tunable technology has to meet the requirements of strong robustness and wide spectral range. We propose a method for the transmission and manipulation of infrared topological photonic crystal valley states based on tunable refractive index method that exhibits broad-spectrum and multi-band characteristics, along with a tunable emission angle. With this structure, different rotational directions of vortex light sources can independently excite the K valley and K' valley within the frequency band ranging from 75.
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