TY - JOUR
T1 - Design of a metasurface-based dual-band Terahertz perfect absorber with very high Q-factors for sensing applications
AU - Janneh, M.
AU - De Marcellis, A.
AU - Palange, E.
AU - Tenggara, A. T.
AU - Byun, D.
N1 - Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/6/1
Y1 - 2018/6/1
N2 - We report on a novel very high Q-factor dual-band Terahertz perfect absorber composed of a metasurface located on top of a flexible polyimide spacer deposited on a silver ground layer. The metasurface is a 2D-array of plasmonic nanoantennas with the shape of two concentric square rings and a cylinder positioned at their centre. By performing numerical simulations, we studied the polarisation insensitive electromagnetic response of the absorber for incident angles varying from 0° up to ±30°. The two resonant modes centred at f1=1.80 THz and f2=2.26 THz have Q-factors Q(f1)=120 and Q(f2)=94 and absorption coefficients A(f1)=99.8% and A(f2)=99.6%. Moreover, we investigated how the resonant mode frequencies change with the refractive index and thickness of transparent analytes adsorbed on the metasurface. In terms of the Refractive Index Units (RIU), we obtained sensitivities equal to 187.5 GHz/RIU and 360 GHz/RIU for the f1 and f2 resonance frequencies, respectively, and figure of merits up to FOM=19.1 and FOM∗=431. These results make the dual-band absorber to be employed as a sensing device able to detect the presence and/or the physical/chemical modifications of the adsorbed analytes. Moreover, we investigated the dependence of the sensitivity as a function of slight modifications of the metasurface nanoantenna shape, demonstrating that a more homogeneous distribution of the electric field intensity on the metasurface improves the sensitivity of the absorber without affecting the Q-factors.
AB - We report on a novel very high Q-factor dual-band Terahertz perfect absorber composed of a metasurface located on top of a flexible polyimide spacer deposited on a silver ground layer. The metasurface is a 2D-array of plasmonic nanoantennas with the shape of two concentric square rings and a cylinder positioned at their centre. By performing numerical simulations, we studied the polarisation insensitive electromagnetic response of the absorber for incident angles varying from 0° up to ±30°. The two resonant modes centred at f1=1.80 THz and f2=2.26 THz have Q-factors Q(f1)=120 and Q(f2)=94 and absorption coefficients A(f1)=99.8% and A(f2)=99.6%. Moreover, we investigated how the resonant mode frequencies change with the refractive index and thickness of transparent analytes adsorbed on the metasurface. In terms of the Refractive Index Units (RIU), we obtained sensitivities equal to 187.5 GHz/RIU and 360 GHz/RIU for the f1 and f2 resonance frequencies, respectively, and figure of merits up to FOM=19.1 and FOM∗=431. These results make the dual-band absorber to be employed as a sensing device able to detect the presence and/or the physical/chemical modifications of the adsorbed analytes. Moreover, we investigated the dependence of the sensitivity as a function of slight modifications of the metasurface nanoantenna shape, demonstrating that a more homogeneous distribution of the electric field intensity on the metasurface improves the sensitivity of the absorber without affecting the Q-factors.
KW - Dual-band perfect absorber
KW - Frequency selective-sensitive metasurface
KW - Terahertz plasmonic sensor
KW - Very high Q-factor sensing device
UR - https://www.scopus.com/pages/publications/85042184406
U2 - 10.1016/j.optcom.2018.02.013
DO - 10.1016/j.optcom.2018.02.013
M3 - Article
AN - SCOPUS:85042184406
SN - 0030-4018
VL - 416
SP - 152
EP - 159
JO - Optics Communications
JF - Optics Communications
ER -