Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Aug 28;22(17):6483.
doi: 10.3390/s22176483.

Design of Ultra-Narrow Band Graphene Refractive Index Sensor

Qianyi Shangguan  1 , Zihao Chen  2 , Hua Yang  3 , Shubo Cheng  1 , Wenxing Yang  1 , Zao Yi  4 , Xianwen Wu  5 , Shifa Wang  6 , Yougen Yi  7 , Pinghui Wu  8
Affiliations

Design of Ultra-Narrow Band Graphene Refractive Index Sensor

Qianyi Shangguan et al. Sensors (Basel). .

Abstract

The paper proposes an ultra-narrow band graphene refractive index sensor, consisting of a patterned graphene layer on the top, a dielectric layer of SiO2 in the middle, and a bottom Au layer. The absorption sensor achieves the absorption efficiency of 99.41% and 99.22% at 5.664 THz and 8.062 THz, with the absorption bandwidths 0.0171 THz and 0.0152 THz, respectively. Compared with noble metal absorbers, our graphene absorber can achieve tunability by adjusting the Fermi level and relaxation time of the graphene layer with the geometry of the absorber unchanged, which greatly saves the manufacturing cost. The results show that the sensor has the properties of polarization-independence and large-angle insensitivity due to the symmetric structure. In addition, the practical application of testing the content of hemoglobin biomolecules was conducted, the frequency of first resonance mode shows a shift of 0.017 THz, and the second resonance mode has a shift of 0.016 THz, demonstrating the good frequency sensitivity of our sensor. The S (sensitivities) of the sensor were calculated at 875 GHz/RIU and 775 GHz/RIU, and quality factors FOM (Figure of Merit) are 26.51 and 18.90, respectively; and the minimum limit of detection is 0.04. By comparing with previous similar sensors, our sensor has better sensing performance, which can be applied to photon detection in the terahertz band, biochemical sensing, and other fields.

Keywords: graphene; refractive index sensor; terahertz waves; ultra-narrow band.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
(a) Three-dimensional view of the ultra-narrowband graphene SPR absorber array (b) Platform of the absorber.
Figure 2
Figure 2
Absorption spectra of ultra-narrow graphene absorber in the range of 5~9 THz with resonance frequency f and absorption bandwidth Bw marked on the graph.
Figure 3
Figure 3
The cross-sectional electric field distribution on the absorber surface in the x-y direction when the incident light frequency is (a) 5.664 THz and (b) 8.062 THz, respectively.
Figure 4
Figure 4
The real part Re(Z) and the imaginary part Im(Z) of the effective impedance Z of the ultra-narrow SPR absorber.
Figure 5
Figure 5
(a) Absorption changing spectra with the Fermi level of graphene increased from 0.50 eV to 0.90 eV. (b) Absorption spectra obtained by increasing the relaxation time of graphene from 0.70 Ps to 5.0 Ps.
Figure 6
Figure 6
With the incident angle of the source increasing from 0° to 70°, (a) the sweep spectra of the absorber under TE and TM polarization. (b) the fitted spectrograms of TE and TM polarization.
Figure 7
Figure 7
With the surrounding refractive index n increasing from 1.00 to 1.08, (a) the absorption changing curves of our absorber; (b) the n-f line chart of two modes; (c) The FWHM and FOM are calculated for the first resonant frequency; (d) The FWHM and FOM are calculated for the second resonant frequency.
Figure 8
Figure 8
The wavelength changed at the two resonance frequencies when the hemoglobin molecular content increased successively from 10 g/L (n = 1.34), 20 g/L (n = 1.36), 30 g/L (n = 1.39) to 40 g/L (n = 1.43).
See this image and copyright information in PMC

References

    1. Zheng Z., Luo Y., Yang H., Yi Z., Zhang J., Song Q., Yang W., Liu C., Wu X., Wu P. Thermal tuning of terahertz metamaterial properties based on phase change material vanadium dioxide. Phys. Chem. Chem. Phys. 2022;24:8846–8853. doi: 10.1039/D2CP01070D. - DOI - PubMed
    1. Chen J., Nie H., Tang C., Cui Y., Yan B., Zhang Z., Kong Y., Xu Z., Cai P. Highly sensitive refractive-index sensor based on strong magnetic resonance in metamaterials. Appl. Phys. Express. 2019;12:052015. doi: 10.7567/1882-0786/ab14fa. - DOI
    1. Zhao F., Lin J., Lei Z., Yi Z., Qin F., Zhang J., Liu L., Wu X., Yang W., Wu P. Realization of 18.97% theoretical efficiency of 0.9 μm thick c-Si/ZnO heterojunction ultrathin-film solar cells via surface plasmon resonance enhancement. Phys. Chem. Chem. Phys. 2022;24:4871–4880. doi: 10.1039/D1CP05119A. - DOI - PubMed
    1. Gu Y.F., Guo B.B., Yi Z., Wu X.W., Zhang J., Yang H. Synthesis of a Self-assembled Dual Morphologies Ag-NPs/SrMoO4 Photocatalyst with LSPR Effect for the Degradation of Methylene Blue Dye. ChemistrySelect. 2022;7:e202201274. doi: 10.1002/slct.202201274. - DOI
    1. Cai L., Zhang Z., Xiao H., Chen S., Fu J. An eco-friendly imprinted polymer based on graphene quantum dots for fluorescent detection of p-nitroaniline. RSC Adv. 2019;9:41383–41391. doi: 10.1039/C9RA08726E. - DOI - PMC - PubMed

LinkOut - more resources