TY - JOUR

T1 - Labyrinth Metasurface Absorber for Ultra-High-Sensitivity Terahertz Thin Film Sensing

AU - Jáuregui-López, Irati

AU - Rodríguez-Ulibarri, Pablo

AU - Urrutia, Aitor

AU - Kuznetsov, Sergei A.

AU - Beruete, Miguel

PY - 2018/10/1

Y1 - 2018/10/1

N2 - In this work, a labyrinth metasurface sensor operating at the low-frequency edge of the THz band is presented. Its intricate shape leads to a high electric field confinement on the surface of the structure, resulting in ultrasensitive performance, able to detect samples of the order of tens of nanometers at a wavelength of the order of millimeters (i.e., five orders of magnitude larger). The sensing capabilities of the labyrinth metasurface are evaluated numerically and experimentally by covering the metallic face with tin dioxide (SnO2) thin films with thicknesses ranging from 24 to 345 nm. A redshift of the resonant frequency is observed as the analyte thickness increases, until reaching a thickness of 20 μm, where the response saturates. A maximum sensitivity of more than 800 and a figure of merit near 4500 nm−1 are achieved, allowing discriminating differences in the SnO2 thickness of less than 25 nm, and improving previous works by a factor of 35. This result can open a new paradigm of ultrasensitive devices based on intricate metageometries overcoming the limitations of classical metasurface sensor designs based on periodic metaatoms.

AB - In this work, a labyrinth metasurface sensor operating at the low-frequency edge of the THz band is presented. Its intricate shape leads to a high electric field confinement on the surface of the structure, resulting in ultrasensitive performance, able to detect samples of the order of tens of nanometers at a wavelength of the order of millimeters (i.e., five orders of magnitude larger). The sensing capabilities of the labyrinth metasurface are evaluated numerically and experimentally by covering the metallic face with tin dioxide (SnO2) thin films with thicknesses ranging from 24 to 345 nm. A redshift of the resonant frequency is observed as the analyte thickness increases, until reaching a thickness of 20 μm, where the response saturates. A maximum sensitivity of more than 800 and a figure of merit near 4500 nm−1 are achieved, allowing discriminating differences in the SnO2 thickness of less than 25 nm, and improving previous works by a factor of 35. This result can open a new paradigm of ultrasensitive devices based on intricate metageometries overcoming the limitations of classical metasurface sensor designs based on periodic metaatoms.

KW - metasurfaces

KW - sensing

KW - terahertz

KW - thin film

KW - GENERATION

KW - SURFACES

UR - http://www.scopus.com/inward/record.url?scp=85052889298&partnerID=8YFLogxK

U2 - 10.1002/pssr.201800375

DO - 10.1002/pssr.201800375

M3 - Letter

AN - SCOPUS:85052889298

VL - 12

JO - Physica Status Solidi - Rapid Research Letters

JF - Physica Status Solidi - Rapid Research Letters

SN - 1862-6254

IS - 10

M1 - 1800375

ER -