Terahertz sensing of 7nm dielectric film with bound states in the continuum metasurfaces
arXiv:1908.03662 · doi:10.1063/1.5110383
Abstract
Fingerprint spectral response of several materials with terahertz electromagnetic radiation indicates that terahertz technology is an effective tool for sensing applications. However, sensing few nanometer thin-film of dielectrics with much longer terahertz waves (1 THz = 0.3 mm) is challenging. Here, we demonstrate a quasi-bound state in the continuum (BIC) resonance for sensing of nanometer scale thin analyte deposited on a flexible metasurface. The large sensitivity originates from strong local field confinement of the quasi-BIC Fano resonance state and extremely low absorption loss of a low-index cyclic olefin copolymer substrate. A minimum thickness of 7 nm thin-film of germanium is sensed on the metasurface, which corresponds to a deep subwavelength length scale of λ/43000, where λ is the resonance wavelength. The low-loss, flexible and large mechanical strength of the quasi-BIC micro structured metamaterial sensor could be an ideal platform for developing ultrasensitive wearable terahertz sensors.
9 pages, 4 figures
References in corpus (3)
- Ultrasensitive THz sensing with high-Q Fano resonances in metasurfaces
- Metamaterial near-field sensor for deep-subwavelength thickness measurements and sensitive refractometry in the terahertz frequency range
- Detection of deep-subwavelength dielectric layers at terahertz frequencies using semiconductor plasmonic resonators
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- Interdigitated Terahertz Metamaterial Sensors: Design with the Dielectric Perturbation Theory
- Robustness of Bound States in the Continuum in Bilayer Structures against Symmetry Breaking
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