Exploiting Localized Surface Plasmon Resonances in Subwavelength Spiral Disks for THz Thin Film Sensing

Applied Sciences

卷:10

Pavel A. Lazorskiy¹  Ruslan R. Hafizov²  Vasily V. Gerasimov²  Sergei A. Kuznetsov² 

[1] Analytical and Technological Research Center, Novosibirsk State University, 2, Pirogov St., 630090 Novosibirsk, Russia;

[2] Budker Institute of Nuclear Physics SB RAS, 11, Ac. Lavrentiev Ave., 630090 Novosibirsk, Russia;

关键词: metasurface;    localized surface plasmon resonance;    thin-film sensor;    terahertz;   

DOI  :  10.3390/app10103595

来源: DOAJ

【 摘 要 】

In this paper, we studied the sensing performance of metasurfaces comprised by spiral-disk-shaped metallic elements patterned on polypropylene substrates, which exhibited localized surface plasmon resonances in the low-frequency region of the terahertz (THz) spectrum (0.2–0.5 THz). Optimal designs of spiral disks with C-shaped resonators placed near the disks were determined and fabricated. The experimentally measured transmittance spectra of the samples coated with very thin photoresistive layers (d ~ 10⁻⁴–10⁻³ λ) showed good agreement with the simulations. The resonance frequency shift Δf increases with increasing d, while saturating near d = 50 µm. The narrow-band magnetic dark modes excited on symmetrical spiral disks with a 90° C-resonator demonstrated very high figure of merit (FOM) values reaching 1670 (RIU·mm)⁻¹ at 0.3 μm thick analyte. The hybrid high order resonances excited on asymmetrical densely packed spiral disks showed about two times larger FOM values (up to 2950 (RIU·mm)⁻¹) compared to symmetrical distantly spaced spirals that resembled the best FOM results found in the literature for metasurfaces fabricated with a similar technique. The demonstrated high sensing performance of spiral disks is evaluated to be promising for bio-sensing applications in the THz range.

【 授权许可】

Unknown