Terahertz Sensing for R/S Chiral Ibuprofen via All-Dielectric Metasurface with Higher-Order Resonance

Abstract

A terahertz (THz) all-dielectric metasurface with crescent cylinder arrays for chiral drug sensing has been demonstrated. Through the multipole expansion method, we theoretically found that breaking the symmetry of the metasurface can excite higher-order resonance modes and provide stronger anisotropy as well as enhanced sensitivity for the surroundings, which gives a better sensing performance than lower-order resonance. Based on the frequency shift and transmittance at higher-order resonance, we carried out the sensing experiments on (R)-(−)-ibuprofen and (S)-(+)-ibuprofen solution on the surface of this metasurface sensor. We were able to monitor the concentrations of ibuprofen solutions, and the maximum sensitivity reached 60.42 GHz/mg. Furthermore, we successfully distinguished different chiral molecules such as (R)-(−)-ibuprofen and (S)-(+)-ibuprofen in the 5 μL trace amount of samples. The maximum differentiation was 18.75 GHz/mg. Our analysis confirms the applicability of this crescent all-dielectric metasurface to enhanced sensing and detection of chiral molecules, which provides new paths for the identification of biomolecules in a trace amount.

Trends in Nanophotonics‐Enabled Optofluidic Biosensors

“…Moreover, many biologically and medically relevant real‐time bioassays are conducted in fluidic buffer environments, which decreases the refractive index contrast between the surface bonded/adsorbed molecules and the dielectric environment compared to measurements in air, reducing the achievable sensitivity. [ 118 ] To address this issue, higher‐order resonances in BIC‐inspired metasurfaces (Figure 2f) have been shown to provide higher spectral resolution and sensing performance than the fundamental modes for detection in solution, as demonstrated by Wang et al., [ 88 ] (Figure 2g) and Shi et al., [ 119 ] indicating a clear advantage of employing such higher‐order resonances for biosensing.…”

Weak Value Amplified Precision Terahertz Spectroscopic Detection of Solid and Liquid Glucose Samples

“…The qualitative and quantitative detection of aqueous biological samples such as amino acids is mainly based on reflective THz-TDS systems, − where the short interaction length between the THz wave and solution results in THz spectra that contain only limited sample information. Periodical metamaterial-based THz sensors designed to improve the precision of THz detection have been proposed. − Nevertheless, these methods require accurate control of the dimension of the periodical structure, complex instruments, and sample-specific advanced nanofabrication. Along the direction of the aforementioned investigations, there is a continued quest for detecting extremely low concentrations and/or mass fractions of target molecules with high resolution.…”

Reconfigurability analysis of an all‐dielectric thermal microfluidic‐based metasurface

“…The periodic arrangement of designed sub-wavelength resonators brings a change in the wave fronts of the incident electromagnetic waves. [1][2][3][4] This principle led to the development of numerous applications using metasurfaces such as metalenses, 5,6 broadband polarization converters, [7][8][9] THz sensors, 2 holograms, 10,11 beam steering, 12,13 and absorbers, 7,14,15 to name a few. All-dielectric metasurfaces, providing additional advantages of low losses, have gained a lot of attention for the development of reconfigurable metasurfaces.…”