Fourier Transformed Terahertz Spectroscopy Inspired Detection of Evanescent Orders in All Dielectric Sub-Wavelength Grating

Rane, Shreeya; Punjal, Ajinkya; Prabhu, S. S.; Chowdhury, Dibakar Roy

doi:10.1109/jstqe.2023.3274418

Cited by 5 publications

(1 citation statement)

References 36 publications

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“…Therefore, the introduction of a supporting film with a dielectric constant close to unity is critical to avoid disturbing the field distribution (i.e., enhancement effects) inside the cavity. In the THz frequency range, FP microcavity has been used for sensitive sensing of gases and liquids; conversely, it has not been considered as a biosensing platform [51][52][53][54][55][56][57][58][59][60]. A careful consideration of the spatial field distribution inside the microcavities is crucial to achieve biological sensing using FP microcavities.…”

Section: Introductionmentioning

confidence: 99%

Developing a Novel Terahertz Fabry–Perot Microcavity Biosensor by Incorporating Porous Film for Yeast Sensing

Kim

Jun

Ahn

2023

Sensors

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We present a novel terahertz (THz) Fabry–Perot (FP) microcavity biosensor that uses a porous polytetrafluoroethylene (PTFE) supporting film to improve microorganism detection. The THz FP microcavity confines and enhances fields in the middle of the cavity, where the target microbial film is placed with the aid of a PTFE film having a dielectric constant close to unity in the THz range. The resonant frequency shift increased linearly with increasing amount of yeasts, without showing saturation behavior under our experimental conditions. These results agree well with finite-difference time-domain (FDTD) simulations. The sensor’s sensitivity was 11.7 GHz/μm, close to the optimal condition of 12.5 GHz/μm, when yeast was placed at the cavity’s center, but no frequency shift was observed when the yeast was coated on the mirror side. We derived an explicit relation for the frequency shift as a function of the index, amount, and location of the substances that is consistent with the electric field distribution across the cavity. We also produced THz transmission images of yeast-coated PTFE, mapping the frequency shift of the FP resonance and revealing the spatial distribution of yeast.

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