TY - JOUR

T1 - Spectral Tuning and Angular–Gap Interrogation of Terahertz Spoof Surface Plasmon Resonances Excited on Rectangular Subwavelength Grating Using Attenuated Total Reflection in Otto Configuration

AU - Kameshkov, Oleg

AU - Gerasimov, Vasily

AU - Goldenberg, Boris

AU - Nazmov, Vladimir

PY - 2025/6/26

Y1 - 2025/6/26

N2 - In this paper, we experimentally investigated the excitation of spoof surface plasmon polaritons (SSPPs) supported by a 1D subwavelength grating with a rectangular profile in the terahertz (THz) frequency range. Using the attenuated total reflection technique and the THz radiation of the Novosibirsk free electron laser, we carried out detailed studies of both angular and gap spectra at several wavelengths. A shallow grating supporting a fundamental mode was fabricated by means of multibeam X-ray lithography and used as a test sample. The results indicated that we achieved 1-THz tunability of resonance in the frequency range from 1.51 to 2.54 THz on a single grating, which cannot be obtained with active tunable metamaterials. The Q factors of the resonances in the angular spectra were within the range of 19.4–37.6, while the resonances of the gap spectra had a Q factor lying within the 1.17–2.03 range. The gap adjustment capability of the setup shown in the work has great potential in modulation of the absorption efficiency, whereas the angular tuning and recording data from each point of the grating will enable real-time monitoring of changes in the surrounding medium. All of this is highly important for enhanced terahertz real-time absorption spectroscopy and imaging.

AB - In this paper, we experimentally investigated the excitation of spoof surface plasmon polaritons (SSPPs) supported by a 1D subwavelength grating with a rectangular profile in the terahertz (THz) frequency range. Using the attenuated total reflection technique and the THz radiation of the Novosibirsk free electron laser, we carried out detailed studies of both angular and gap spectra at several wavelengths. A shallow grating supporting a fundamental mode was fabricated by means of multibeam X-ray lithography and used as a test sample. The results indicated that we achieved 1-THz tunability of resonance in the frequency range from 1.51 to 2.54 THz on a single grating, which cannot be obtained with active tunable metamaterials. The Q factors of the resonances in the angular spectra were within the range of 19.4–37.6, while the resonances of the gap spectra had a Q factor lying within the 1.17–2.03 range. The gap adjustment capability of the setup shown in the work has great potential in modulation of the absorption efficiency, whereas the angular tuning and recording data from each point of the grating will enable real-time monitoring of changes in the surrounding medium. All of this is highly important for enhanced terahertz real-time absorption spectroscopy and imaging.

KW - Otto configuration

KW - angular and gap interrogation

KW - attenuated total reflection

KW - frequency tunability

KW - monochromatic radiation source

KW - spoof surface plasmon resonance

UR - https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=105011670674&origin=inward

UR - https://www.mendeley.com/catalogue/6b3cebd4-fec2-374e-b7c4-5ccf67aaad22/

U2 - 10.3390/photonics12070651

DO - 10.3390/photonics12070651

M3 - Article

VL - 12

JO - Photonics

JF - Photonics

SN - 2304-6732

IS - 7

M1 - 651

ER -