Abstract-Enhanced terahertz fingerprint detection with ultrahigh sensitivity using the cavity defect modes

Xiaomei Shi,  Zhanghua Han, 

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  • https://www.nature.com/articles/s41598-017-13612-9
    We report a new scheme of realizing terahertz fingerprint detection with ultrahigh sensitivity. Instead of using the direct absorption of terahertz through a bare sample in the regular transmission scheme, a cavity mode resonating at the characteristic frequency of the sample is used and due to the high dependence of the cavity mode transmission on the material loss, an amplified transmission decaying is observed when the sample is loaded into the cavity. Furthermore, this scheme retains the feature of substance identification. A one-dimensional photonic crystal cavity is used as the example for the detection of α-lactose and an efficient detection of 10 nm α-lactose can be achieved, which corresponds to 1/57000 of the free space wavelength at the characteristic frequency of 0.529 THz, exhibiting a sensitivity over 400 times higher than the regular transmission method.

Abstract-Cavity enhanced terahertz fingerprint detection with ultrahigh sensitivity

Xiaomei Shi, Zhanghua Han

(Submitted on 5 Jun 2017)

     https://arxiv.org/abs/1706.01976

We report a new scheme of realizing terahertz fingerprint detection with ultrahigh sensitivity. Instead of using the direct absorption of terahertz through a bare sample in the regular transmission scheme, a cavity mode resonating at the characteristic frequency of the sample is used and due to the high dependence of the cavity mode transmission on the material loss, an amplified transmission decaying is observed when the sample is loaded into the cavity. Furthermore, this scheme retains the feature of substance identification. A one-dimensional photonic crystal cavity is used as the example for the detection of {\alpha}-lactose and an efficient detection of 7nm {\alpha}-lactose can be achieved, which corresponds to 1/80000 of the free space wavelength at the characteristic frequency of 0.529THz, exhibiting sensitivity 500 times higher than the regular method.

Abstract-Enhanced terahertz sensing with a coupled comb-shaped spoof surface plasmon waveguide

Xiaomei Shi, Jianyuan Qin, and Zhanghua Han

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-1-278

A comb-shaped waveguide based on the excitation of coupled spoof surface plasmon (CSSP) mode is investigated, and is found to have a pronounced effect for the enhancement of fingerprint detection sensitivity in the terahertz (THz) regime. Composed of two oppositely oriented metal stripes with single-side comb-shaped corrugations, the waveguide is formed due to the coupling of SSP modes supported by metal corrugations on both sides and the mode is tightly localized between the central gap, which provides a perfect site for accommodating the samples in THz sensing. The effective detection of thin-layer lactose is given as an example to demonstrate the sensitive detection of it at a thickness of only a few microns. A transmission spectrum through the waveguide with a pronounced dip at its characteristic absorption frequency of 0.529THz is shown, which can never be observed using the transmission through a lactose layer with the same thickness.

© 2017 Optical Society of America

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