Nondestructive testing and imaging of corrosion thickness of steel plates using THz-TDS

Xu, Ying; Jiang, Xuelei

doi:10.1016/j.infrared.2022.104467

Cited by 11 publications

(1 citation statement)

References 29 publications

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“…Therefore, it is unsuitable for broadband terahertz imaging systems. The terahertz imaging system [23][24][25] based on the terahertz time-domain spectrum system uses electrooptic sampling [26][27] mode, and the direct use of terahertz vortex devices will change the spatial distribution of the terahertz field. Thus changing the spatial distribution of the modulation phase in the electro-optic crystal, results in the loss of essential information in the vicinity of the output image center, and no apparent edge detail enhancement.…”

Section: Introductionmentioning

confidence: 99%

Broadband THz Edge-Enhanced Imaging Technology Based on Electro-Optic Sampling

Yuan

Liu

Lin

et al. 2023

J. Phys.: Conf. Ser.

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Based on the radial Hilbert transform of spatial filtering and electro-optical sampling, we propose a broadband terahertz edge-enhanced imaging method in this work. Instead of using a narrow-band THz vortex phase plate, here we use vortex ultrashort laser pulse to realize the THz enhancement imaging which can be applied for few-cycle THz imaging. The principle of edge enhancement is analyzed theoretically, and the analytical expression of the final terahertz imaging is derived. We found that edge-enhancement imaging corresponds to the nonlinear term of the THz field, and the background and linear terms can be suppressed when the static birefringent phase is set to zero. The simulations show that our method can effectively improve the contrast and signal-to-noise ratio of terahertz imaging.

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Section: Introductionmentioning

confidence: 99%

Broadband THz Edge-Enhanced Imaging Technology Based on Electro-Optic Sampling

Yuan

Liu

Lin

et al. 2023

J. Phys.: Conf. Ser.

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Terahertz Sensing Based on Floating Bilayer Metasurface with Toroidal Dipole Resonance Toward Ultra‐High Sensitivity

Liu,

Xiao,

Qin

2024

Advanced Optical Materials

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Metasurface structures have proven to be effective in enhancing terahertz sensing signals and can thus be used as sensors to improve terahertz detection sensitivity. However, the sensitivity is limited by the poor spatial overlap between the analytes and the local electric field of the metasurface. In this work, a novel design of a floating bilayer metasurface structure for terahertz sensing is proposed and investigated. This structure supports a sharp toroidal dipole resonance and can concentrate near‐field energy on the analyte and metal atoms rather than on the substrate surface by floating the metal atoms. Consequently, the sensitivity is significantly improved to as high as 362 GHz RIU−1; theoretically, this is approximately 2.6 times higher than that of the common metasurface. The ability of the floating bilayer metasurface to quantitatively detect chlorothalonil is experimentally demonstrated. The resonance peak shows a significant frequency shift of 7 GHz for a change of 0.0001 mg dL−1 in chlorothalonil concentration, reaching up to 86 GHz when the change in chlorothalonil concentration is 100 mg dL−1; this is approximately 6.6 times higher than that of the common metasurface. This work provides opportunities for metasurface to realize ultrasensitive sensing in the terahertz regime.

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