Terahertz synthetic aperture in-line holography with intensity correction and sparsity autofocusing reconstruction

Li, Zeyu; Zou, Ruijiao; Kong, Weipeng; Wang, Xuemin; Deng, Qinghua; Yan, Qiang; Qin, Yu; Wu, Weidong; Zhou, Xun

doi:10.1364/prj.7.001391

Cited by 25 publications

(11 citation statements)

References 33 publications

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“…Namely edge effects, induced by the limited sensor dimensions are impacting the wavefront uniformity. Through algorithmic extrapolation procedures [16,62], or experimentally, with the mapping of a wider imaging field through the lateral displacement of the camera [27,63] combined with the longitudinal multi-plane OTG recording, the enhanced retrieval of complex wavefront profiles would be expected.…”

Section: Discussionmentioning

confidence: 99%

“…In this field, THz imaging [1][2][3] represents one of the most promising approaches, since it provides spatially resolved information about the investigated objects. THz phase imaging (THz PI) [4,5], which includes pulse time-domain holography (PTDH) [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] as well as continuous wave (CW) holography [23][24][25][26][27][28][29][30], Hartmann wavefront sensing [31][32][33][34][35], shearorgaphy [36], ptychography [37][38][39][40][41], and other phase retrieval techniques [42][43][44][45][46][47][48][49], ...…”

Section: Introductionmentioning

confidence: 99%

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Single-scan multiplane phase retrieval with a radiation of terahertz quantum cascade laser

et al. 2022

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Terahertz phase retrieval from a set of axially separated diffractive intensity distributions is a promising single-beam computational imaging technique that ensures the obtention of high spatial resolutions and phase wavefronts, but remains restricted by time-consuming data acquisition processes. In this work, we have adopted an approach, relying on the radiation of a quantum cascade laser and the implementation of an express single-scan measurement of intensity distributions through the continuous on-the-go displacement of a high-sensitivity antenna-coupled microbolometer sensor array. In addition to the simplicity of this practical implementation and the minimization of measurement times, such an approach overcomes the problem of preliminary optimal selections of transverse intensity distributions used in the iterative phase retrieval algorithm and guarantees the required data diversity for high-quality wavefront reconstruction.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Single-scan multiplane phase retrieval with a radiation of terahertz quantum cascade laser

et al. 2022

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“…The basic outline of the dehydrated mosquito could be observed in the reconstructed images. In 2019, Li et al further modified the in-line CW THD system based on a 4.3 THz QCL and a microbolometer detector [64,65]. Both the synthetic aperture algorithm and shortening the distance together can improve the resolution.…”

Section: Cw Thz Digital Holographymentioning

confidence: 99%

“…The profile characteristics and relative optical thickness distribution of the asparagus fern were obtained by unwrapped phase'images. 3 THz QCL and a microbolometer detector [64,65]. Both the synthetic aperture algorithm and shortening the distance together can improve the resolution.…”

Section: Cw Thz Digital Holographymentioning

confidence: 99%

Continuous-Wave THz Imaging for Biomedical Samples

et al. 2020

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In the past few decades, the applications of terahertz (THz) spectroscopy and imaging technology have seen significant developments in the fields of biology, medical diagnosis, food safety, and nondestructive testing. Label-free diagnosis of malignant tumours has been obtained and also achieved significant development in THz biomedical imaging. This review mainly presents the research status and prospects of several common continuous-wave (CW) THz medical imaging systems and applications of THz medical imaging in biological tissues. Here, we first introduce the properties of THz waves and how these properties play a role in biomedical imaging. Then, we analyse both the advantages and disadvantages of the CW THz imaging methods and the progress of these methods in THz biomedical imaging in recent ten years. Finally, we summarise the obstacles in the way of the application of THz bio-imaging application technology in clinical detection, which need to be investigated and overcome in the future.

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“…Therefore, developing a new THz imaging method for low-contrast objects is of great importance. As one of the last mastered frequency ranges of the electromagnetic spectrum, the THz band provides great potential for modern imaging methods which have been widely applied in other spectral regions [6][7][8][9][10][11][12][13][14][15]. Notably, THz imaging techniques can be applied in various fields, such as security screening [16,17], non-destructive testing [18][19][20], biological detection [1,21], and data-rata communications [22,23].…”

Section: Introductionmentioning

confidence: 99%

Terahertz Spiral Spatial Filtering Imaging

Liu

Zhao

et al. 2021

Applied Sciences

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In this paper, we propose a terahertz (THz) spiral spatial filtering (SSF) imaging method that can enable image contrast enhancement. The related theory includes three main steps: (1) the THz image of the target is Fourier transformed to the spatial spectrum distribution; (2) the spatial spectrum is modulated by a spiral phase at the Fourier plane; (3) the filtered spatial spectrum is inverse Fourier transformed to the desired THz image. Meanwhile, analytic expression of the final THz image is derived. Due to the unique nature of the spiral phase, THz image contrast enhancement can be achieved and verified by various simulated target images with different contrasts. In our designed THz SSF imaging system, Fourier transform is carried out by the lens, and the spiral phase is acquired by the spiral phase plate (SPP). Proof-of-principle experiments with three different types of targets (carved metal letters, a high-density polyethylene (HDPE) piece with a scratch, and a leaf) were carried out, and the effectiveness of contrast enhancement and edge extraction on the THz reconstruction images was validated.

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Terahertz synthetic aperture in-line holography with intensity correction and sparsity autofocusing reconstruction

Cited by 25 publications

References 33 publications

Single-scan multiplane phase retrieval with a radiation of terahertz quantum cascade laser

Single-scan multiplane phase retrieval with a radiation of terahertz quantum cascade laser

Continuous-Wave THz Imaging for Biomedical Samples

Terahertz Spiral Spatial Filtering Imaging

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