Depth resolution enhancement of terahertz deconvolution by autoregressive spectral extrapolation

Dong, Junliang; Locquet, Alexandre; Citrin, D. S.

doi:10.1364/ol.42.001828

Cited by 35 publications

(17 citation statements)

References 17 publications

(20 reference statements)

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“…The first perfect metamaterial absorber is proposed and demonstrated by Landy [22]. Thereafter, perfect metamaterial absorbers have been developed rapidly [23–31], which can be generally classified as narrowband absorbers and broadband absorbers according to their different application requirements. Generally, the broadband absorbers can be used in energy harvestor while the narrowband absorbers are used in sensor and monochromatic photodetectors.…”

Section: Introductionmentioning

confidence: 99%

Ultra-narrow Band Perfect Absorber and Its Application as Plasmonic Sensor in the Visible Region

Liu

et al. 2017

Nanoscale Res Lett

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We propose and numerically investigate a perfect ultra-narrowband absorber with an absorption bandwidth of only 1.82 nm and an absorption efficiency exceeding 95% in the visible region. We demonstrate that the perfect ultra-narrowband absorption is ascribed to the coupling effect induced by localized surface plasmon resonance. The influence of structural dimensions on the optical performance is also investigated, and the optimal structure is obtained with the extremely low reflectivity (0.001) of the resonance dip. The perfect absorber can be operated as a refractive index sensor with a sensitivity of around 425 nm/RIU and the figure of merit (FOM) reaching 233.5, which greatly improves the accuracy of the plasmonic sensors in visible region. Moreover, the corresponding figure of merit (FOM*) for this sensor is also calculated to describe the performance of the intensity change detection at a fixed frequency, which can be up to 1.4 × 105. Due to the high sensing performance, the metamaterial structure has great potential in the biological binding, integrated photodetectors, chemical applications and so on.

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Section: Introductionmentioning

confidence: 99%

Ultra-narrow Band Perfect Absorber and Its Application as Plasmonic Sensor in the Visible Region

Liu

et al. 2017

Nanoscale Res Lett

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“…The depth resolution of THz reflectometry is greatly enhanced by exploiting sparsity-based deconvolution. Indeed, conventional deconvolution methods, such as FWDD, entirely fail to reveal the underlying stratigraphy in easel paintings, because FWDD actually involves filtering out low- and high-frequency noise introduced from the division operation in the conventional deconvolution process, and therefore, narrows the bandwidth of the resulting impulse-response function 29 . Sparsity-based deconvolution is a pure time-domain method which does not introduce the low- and high-frequency noise, and is able to yield an enhanced depth resolution and achieve a more clear representation of the stratigraphy.…”

Section: Discussionmentioning

confidence: 99%

Global mapping of stratigraphy of an old-master painting using sparsity-based terahertz reflectometry

Dong

Locquet

Melis³

et al. 2017

Sci Rep

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The process by which art paintings are produced typically involves the successive applications of preparatory and paint layers to a canvas or other support; however, there is an absence of nondestructive modalities to provide a global mapping of the stratigraphy, information that is crucial for evaluation of its authenticity and attribution, for insights into historical or artist-specific techniques, as well as for conservation. We demonstrate sparsity-based terahertz reflectometry can be applied to extract a detailed 3D mapping of the layer structure of the 17th century easel painting Madonna in Preghiera by the workshop of Giovanni Battista Salvi da Sassoferrato, in which the structure of the canvas support, the ground, imprimatura, underpainting, pictorial, and varnish layers are identified quantitatively. In addition, a hitherto unidentified restoration of the varnish has been found. Our approach unlocks the full promise of terahertz reflectometry to provide a global and detailed account of an easel painting’s stratigraphy by exploiting the sparse deconvolution, without which terahertz reflectometry in the past has only provided a meager tool for the characterization of paintings with paint-layer thicknesses smaller than 50 μm. The proposed modality can also be employed across a broad range of applications in nondestructive testing and biomedical imaging.

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“…Our previous work has demonstrated the power of THz deconvolution to resolve overlapping echoes associated with closely-spaced features in depth [18][19][20]. In short, THz deconvolution aims to reconstruct the impulse-response function, that is intrinsic to the sample and independent of the THz pulse employed, which should ideally consist of a sequence of ideal impulses corresponding to reflections from the interfaces of a stratified system [21]. With THz deconvolution, the depth-resolution of THz imaging can be greatly enhanced.…”

Section: Thz Subsurface Spectral Imagingmentioning

confidence: 99%

Visualization of subsurface damage in woven carbon fiber-reinforced composites using polarization-sensitive terahertz imaging

Dong

Pomarède

Chehami

et al. 2018

NDT & E International

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Polarization-sensitive terahertz imaging is applied to characterize subsurface damage in woven carbon fiberreinforced composite laminates in this study. Terahertz subsurface spectral imaging based on terahertz deconvolution is tailored and applied to detect, in a nondestructive fashion, the subsurface damage within the first ply of the laminate caused by a four-point bending test. Subsurface damage types, including matrix cracking, fiber distortion/fracture, as well as intra-ply delamination, are successfully characterized. Our results show that, although the conductivity of carbon fibers rapidly attenuates terahertz propagation with depth, the imaging capability of terahertz radiation on woven carbon fiber-reinforced composites can nonetheless be significantly enhanced by taking advantage of the terahertz polarization and terahertz deconvolution. The method demonstrated in this study is capable of extracting and visualizing a number of fine details of the subsurface damage in woven carbon fiber-reinforced composites, and the results achieved are confirmed by comparative studies with X-ray tomography.

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Depth resolution enhancement of terahertz deconvolution by autoregressive spectral extrapolation

Cited by 35 publications

References 17 publications

Ultra-narrow Band Perfect Absorber and Its Application as Plasmonic Sensor in the Visible Region

Ultra-narrow Band Perfect Absorber and Its Application as Plasmonic Sensor in the Visible Region

Global mapping of stratigraphy of an old-master painting using sparsity-based terahertz reflectometry

Visualization of subsurface damage in woven carbon fiber-reinforced composites using polarization-sensitive terahertz imaging

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