Cross‐Wavelength Hierarchical Metamaterials Enabled for Trans‐Scale Molecules Detection Simultaneously

Abstract

Metamaterials have attracted increasing attention in sensing applications. However, the critical feature sizes of meta‐atom span several orders of magnitude in length scale, almost all the metamaterials are designed to operate at limited bands. It is challenging for a single type of meta‐atom with ultra‐broadband adaptability. Inspired by the natural hierarchical architectures, herein, the authors introduce a new constructing scheme of cross‐wavelength hierarchical metamaterials with a single type of meta‐atom that can realize enhancement of terahertz (THz) resonance and surface‐enhanced Raman scattering (SERS) at the same time. By combining multiple subwavelength structures at different hierarchical levels into a single meta‐atom, the obtained metamaterial can operate in two frequencies and realize multiple functionalities. Armed with this hierarchical metamaterial, detecting analytes as small as sub‐nanoscale chemical molecules or as big as microscale biomolecules simultaneously can be realized in one single metamaterial for the first time. As a proof‐of‐concept example, a smart sensory packaging is developed, which allowed them to real‐time monitor the kinetic growth of pathogenic bacteria and their metabolites in food without opening the packaging. They believe that their work will provide a valuable example that satisfies the unmet need for multiscale functional meta‐devices.

Ultra-wideband terahertz fingerprint enhancement sensing and inversion model supported by single-pixel reconfigurable graphene metasurface

“…However, the material and structure of previous metallic or dielectric metasurfaces are difficult to adjust after fabrication. And the isolated and narrow-band distribution characteristics of their resonance peaks will result in extremely limited information on frequency shift or amplitude change detected [27][28][29][30][31]. More importantly, obtaining multiple THz fingerprint features ( ≥ 2) of the analyte in the broadband range is the key to further study the molecular conformation and accurately distinguish different samples to avoid 'false positive' diagnosis [32][33][34].…”

Plasma amplifiers: multiscale light-enhanced uniform SERS composite substrates for breaking through resonance limitations

“…[1][2][3][4][5] To enhance Raman signals, nanostructured noble metal materials have gained immense popularity owing to their unique plasmonic properties. [6][7][8][9][10] Through nanoscale modulation of plasmons, surface-enhanced Raman spectroscopy (SERS) can easily enhance the Raman signal by more than six orders of magnitude. [11][12][13][14][15] However, traditional noble metal nanoparticles (NPs) have their limitations, encompassing restricted signal enhancement, uneven distribution of hotspots, and poor reproducibility.…”

Design and experimental realization of triple-band electromagnetically induced transparency terahertz metamaterials employing two big-bright modes for sensing applications

“…In these functional devices, EIT resonance devices, as a research hotspot, have received considerable interest. [11][12][13][14][15] The EIT effect is initially manifested as the absorption of the source by the medium that is weakened or even disappeared under the action of the incident light field, that is, the medium becomes transparent from opaque for a specific electromagnetic wave band. 16 The remarkable feature of similar EIT phenomena in metamaterials is that a narrow transmission window appears in the spectrum, and thus they have wide applications in biosensors, 17 modulators, 18 switches, 19 and optical storage 20 and in the slow light effect.…”