http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Janneh, M.,De Marcellis, A.,Palange, E.,Tenggara, A.T.,Byun, D. Elsevier 2018 OPTICS COMMUNICATIONS - Vol.416 No.-
<P><B>Abstract</B></P> <P>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 <SUB> f 1 </SUB> = 1 .80 THz and <SUB> f 2 </SUB> = 2 .26 THz have Q -factors Q ( <SUB> f 1 </SUB> ) = 120 and Q ( <SUB> f 2 </SUB> ) = 94 and absorption coefficients A ( <SUB> f 1 </SUB> ) = 99 . 8 % and A ( <SUB> f 2 </SUB> ) = 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 <SUB> f 1 </SUB> and <SUB> f 2 </SUB> resonance frequencies, respectively, and figure of merits up to FOM = 19 . 1 and <SUP> FOM ∗ </SUP> = 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.</P>