TY - JOUR

T1 - Exploiting localized surface plasmon resonances in subwavelength spiral disks for THz thin film sensing

AU - Gerasimov, Vasily V.

AU - Hafizov, Ruslan R.

AU - Kuznetsov, Sergei A.

AU - Lazorskiy, Pavel A.

PY - 2020/5/22

Y1 - 2020/5/22

N2 - In this paper, we studied the sensing performance of metasurfaces comprised by spiraldisk-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° Cresonator demonstrated very high figure of merit (FOM) values reaching 1670 (RIUmm)-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 (RIUmm)-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.

AB - In this paper, we studied the sensing performance of metasurfaces comprised by spiraldisk-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° Cresonator demonstrated very high figure of merit (FOM) values reaching 1670 (RIUmm)-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 (RIUmm)-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.

KW - Localized surface plasmon resonance

KW - Metasurface

KW - Terahertz

KW - Thin-film sensor

KW - WAVE

KW - localized surface plasmon resonance

KW - terahertz

KW - thin-film sensor

KW - metasurface

UR - http://www.scopus.com/inward/record.url?scp=85085627837&partnerID=8YFLogxK

U2 - 10.3390/app10103595

DO - 10.3390/app10103595

M3 - Article

AN - SCOPUS:85085627837

VL - 10

JO - Applied Sciences (Switzerland)

JF - Applied Sciences (Switzerland)

SN - 2076-3417

IS - 10

M1 - 3595

ER -