A pixelated frequency-agile metasurface for broadband terahertz molecular fingerprint sensing

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Sun, L., Xu, L. ORCID: 0000-0001-9071-4311, Wang, J., Jiao, Y., Ma, Z., Ma, Z., Chang, C., Yang, X. and Wang, R., 2022. A pixelated frequency-agile metasurface for broadband terahertz molecular fingerprint sensing. Nanoscale, 14 (27), pp. 9681-9685. ISSN 2040-3364

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Official URL: https://doi.org/10.1039/d2nr01561g

Abstract

Terahertz (THz) plasmonic resonance based on the arbitrarily designed resonance metasurface is the key technique of choice for enhancing fingerprint absorption spectroscopy identification of biomolecules. Here, we report a broadband THz micro-photonics sensor based on the pixelated frequency-agile metasurface and illustrate its application ability to enhance and differentiate the detection of broadband absorption fingerprint spectrum. The design uses symmetrical metal C-shape resonators with the functional graphene micro-ribbons selectively patterned into the gaps. A strong electric resonance with high quality factor has been formed, consisting of electric dipole mode associated with the excitation of a dark toroidal dipole (TD) mode through the coupling from the electric dipole moment of individual frequency-agile meta-unit. The resonance positions are nearly linearly modulated with the varying Fermi level of graphene. The configuration arranges a certain metapixel of the metasurface to multiple response spectra assembling a one-to-many mapping between spatial and spectral information which is instrumental in greatly shrinking the actual size of the sensor. By the synchronous regulation of graphene and C-shape rings, we have obtained highly surface-sensitive resonances over a wide spectral range (~ 1.5 THz) with a spectral resolution less than 20 GHz. The target multiple enhanced absorption spectrum of glucose molecules is read out in a broadband region with high sensitivity. More importantly, the design can be extended to cover a larger spectral region by altering the range of geometrical parameters. Our microphotonic technique can resolve absorption fingerprints without the need for spectrometry and frequency scanning, thereby providing an approach for highly sensitive and versatile miniaturized THz spectroscopy devices.

Item Type:

Journal article

Alternative Title:

Pixelated frequency-agile metasurface for broadband terahertz molecular fingerprint sensing

Publication Title:

Nanoscale

Creators:

Sun, L., Xu, L., Wang, J., Jiao, Y., Ma, Z., Ma, Z., Chang, C., Yang, X. and Wang, R.

Publisher:

Royal Society of Chemistry (RSC)

Date:

2022