High-resolution terahertz inline digital holography based on quantum cascade laser

Deng, Qinghua; Li, Weihua; Wang, Xuemin; Li, Zeyu; Huang, Haochong; Shen, Chengmin; Zhan, Zhiqiang; Zou, Ruijiao; Jiang, Tao; Wu, Weidong

doi:10.1117/1.oe.56.11.113102

Cited by 10 publications

(5 citation statements)

References 25 publications

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“…The spatial resolution of digital holography [395] and synthetic aperture imaging [396,397] is determined by a scheme of interferometric pattern detection and by a data processing routine applied to the inverse problem solution [398][399][400]. This technique allows one to obtain close-towavelength or slightly sub-wavelength resolution THz images; for example, the ability to achieve 1.0-1.2 λresolution THz synthetic aperture imaging was demonstrated in [401,402]. Furthermore, they are capable of achieving realtime operation regimes [400].…”

Section: Terahertz-wave Delivery To Difficult-to-access Tissue and In...mentioning

confidence: 99%

“…Furthermore, they are capable of achieving realtime operation regimes [400]. THz digital holography methods were applied for imaging the whole insect [401] and structure of insect wings [402,403], breast tissue cancer [404] and human hepatocellular carcinoma [405], as well as for controlling the dehydration dynamics in tissues [406]. Slightly sub-wavelength resolution and a high acquisition rate are the advantages of holographic THz imaging.…”

Section: Terahertz-wave Delivery To Difficult-to-access Tissue and In...mentioning

confidence: 99%

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The progress and perspectives of terahertz technology for diagnosis of neoplasms: a review

Zaytsev

Dolganova

Chernomyrdin

et al. 2019

J. Opt.

163

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Over the past few decades, significant attention has been paid to the biomedical applications of terahertz (THz) technology. Nowadays, THz spectroscopy and imaging have allowed numerous demanding problems in the biological, medical, food, plant and pharmaceutical sciences to be solved. Among the biomedical applications, the label-free diagnosis of malignant and benign neoplasms represents one of the most attractive branches of THz technology. Despite this attractiveness, THz diagnosis methods are still far from being ready for use in medical practice. In this review, we consider modern research results in the THz diagnosis of malignant and benign neoplasms, along with the topical research and engineering problems which restrain the translation of THz technology to clinics. We start by analyzing the common models of THz-wave-tissue interactions and the effects of tissue exposure to THz waves. Then, we discuss the existing modalities of THz spectroscopic and imaging systems, which have either already been applied in medical imaging, or hold strong potential. We summarize the earlier-reported and original results of the THz measurements of neoplasms with different nosology and localization. We pay attention to the origin of contrast between healthy and pathological tissues in the THz spectra and images, and discuss the prospects of THz technology in

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Section: Terahertz-wave Delivery To Difficult-to-access Tissue and In...mentioning

confidence: 99%

Section: Terahertz-wave Delivery To Difficult-to-access Tissue and In...mentioning

confidence: 99%

The progress and perspectives of terahertz technology for diagnosis of neoplasms: a review

Zaytsev

Dolganova

Chernomyrdin

et al. 2019

J. Opt.

163

View full text Add to dashboard Cite

show abstract

“…According to them, the tested uncooled microbolometers are 40 times more sensitive than the pyroelectric camera Pyrocam III. As a consequence, the high detectivity of infrared microbolometers allows working with mW-level output sources such as QCLs or various FIRL lines [82,[110][111][112][113]. Their pixel pitch of 17-25 µm is ideal for off-line holography, as it allows large off-axis angles.…”

Section: Source-detector Systemsmentioning

confidence: 99%

“…As an alternative, a synthetic aperture scheme uses real holograms to increase the resolution, and is an effective solution for THz in-line digital holography, as well. Examples were reported in [110,111], reconstructing features as low as λ. In Ref.…”

Section: In-line Digital Holographymentioning

confidence: 99%

THz coherent lensless imaging

et al. 2019

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Imaging with THz radiation has proved an important tool for both fundamental science and industrial use. Here we review a class of THz imaging implementations, named coherent lensless imaging, that reconstruct the coherent response of arbitrary samples with a minimized experimental setup based only on a coherent source and a camera. After discussing the appropriate sources and detectors to perform them, we detail the fundamental principles and implementations of THz digital holography and phase retrieval. These techniques owe a lot to imaging with different wavelengths, yet innovative concepts are also being developed in the THz range and are ready to be applied in other spectral ranges. This makes our review useful for both the THz and imaging communities, and we hope it will foster their interaction.

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“…In the entire electromagnetic spectrum, the terahertz (THz) region (roughly defined between 0.1 and 10 THz) 11 – 13 shows great advantages in spectroscopy, imaging, metrology, and communications, on account of its unique characteristics, e.g., covering vibrational and rotational absorption lines (fingerprints) of plentiful molecules, transparency to some packaging materials, and broader potential communication bandwidth compared to microwave 14 – 18 Highly stabilized THz radiation sources are of great importance for the various applications mentioned above. Among different THz radiation sources, the electrically pumped THz quantum cascade laser (QCL), showing high output power, 19 wide emission frequency range, 20 , 21 high operation temperature, 22 – 24 high-quality far-field beam, 25 , 26 and narrow intrinsic linewidth, 27 is an ideal candidate for high-precision frequency comb operation 28 , 29 .…”

Section: Introductionmentioning

confidence: 99%

Relative phase locking of a terahertz laser system configured with a frequency comb and a single-mode laser

Guan

et al. 2023

Adv. Photon. Nexus

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Stable operation is one of the most important requirements for a laser source for high-precision applications. Many efforts have been made to improve the stability of lasers by employing various techniques, e.g., electrical and/or optical injection and phase locking. However, these techniques normally involve complex experimental facilities. Therefore, an easy implementation of the stability evaluation of a laser is still challenging, especially for lasers emitting in the terahertz (THz) frequency range because the broadband photodetectors and mature locking techniques are limited. In this work, we propose a simple method, i.e., relative phase locking, to quickly evaluate the stability of THz lasers without a need of a THz local oscillator. The THz laser system consists of a THz quantum cascade laser (QCL) frequency comb and a single-mode QCL. Using the single-mode laser as a fast detector, heterodyne signals resulting from the beating between the singlemode laser and the comb laser are obtained. One of the heterodyne beating signals is selected and sent to a phase-locked loop (PLL) for implementing the relative phase locking. Two kinds of locks are performed by feeding the output error signal of the PLL, either to the comb laser or to the single-mode laser. By analyzing the current change and the corresponding frequency change of the PLL-controlled QCL in each phase-locking condition, we, in principle, are able to experimentally compare the stability of the emission frequency of the single-mode QCL (f s ) and the carrier envelope offset frequency (f CEO ) of the QCL comb. The experimental results reveal that the QCL comb with the repetition frequency injection locked demonstrates much higher stability than the single-mode laser. The work provides a simple heterodyne scheme for understanding the stability of THz lasers, which paves the way for the further locking of the lasers and their high-precision applications in the THz frequency range.

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High-resolution terahertz inline digital holography based on quantum cascade laser

Cited by 10 publications

References 25 publications

The progress and perspectives of terahertz technology for diagnosis of neoplasms: a review

The progress and perspectives of terahertz technology for diagnosis of neoplasms: a review

THz coherent lensless imaging

Relative phase locking of a terahertz laser system configured with a frequency comb and a single-mode laser

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