THz Spectroscopy by Narrow Spectral Emission of Quantum Cascade Lasers for Medical Applications

Hartnagel, H.L.; Sirkeli, Vadim P.; Acedo, Pablo

doi:10.1109/cas52836.2021.9604138

Cited by 2 publications

(1 citation statement)

References 37 publications

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“…Terahertz wave is an electromagnetic wave with a frequency of 0.1T ∼ 10THz, which is located between microwave and visible light [1], compared with the traditional infrared imaging system, the THz imaging system made of blackbody radiation and thermal background radiation emitted by natural objects has the advantages of high penetration, high safety, and metal sensitivity [2][3]. Therefore, the imaging system based on THz wave is widely used in the fields of detection [4], medical treatment [5], security [6][7], and nondestructive testing [8][9], especially in the security system, the passive terahertz imaging system can detect and image the contour information of all kinds of hidden metal dangerous goods. Therefore, the terahertz imaging system has great potential for practical application.…”

Section: Introductionmentioning

confidence: 99%

UHA‐CycleGAN: Unpaired hybrid attention network based on CycleGAN for terahertz image super‐resolution

Liu

Guo

Liu

2023

IET Image Processing

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In recent years, terahertz imaging technology has been widely used in security, medicine, and other fields. However, the image resolution is low due to the limits of imaging equipment and diffraction. Traditional super-resolution methods based on machine learning use artificial paired image datasets, and their image degradation process is quite different from the actual terahertz imaging mechanism. In the paper, an unpaired hybrid attention network is proposed, using the real unpaired high-resolution and low-resolution terahertz images as the original input, two sub-networks are trained: degenerate reconstruction network and super-resolution network. The degenerate reconstruction network is used to learn the degradation process of the real terahertz imaging system, and reconstruct the generated degradation images into the fixed mapping down-sampled image of highresolution terahertz image. The super-resolution network uses the generated paired image with fixed correspondence to train the super-resolution network of paired terahertz images, to improve the imaging resolution of the network in the super-resolution work of real low-resolution terahertz images. In addition, the no-reference image quality evaluation system is introduced to objectively evaluate the network performance. The experimental results show that the UHA-CycleGAN network outperforms the traditional paired super-resolution network on both open-source and self-built datasets.

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Section: Introductionmentioning

confidence: 99%

UHA‐CycleGAN: Unpaired hybrid attention network based on CycleGAN for terahertz image super‐resolution

Liu

Guo

Liu

2023

IET Image Processing

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Doping engineering: Next step toward room temperature performance of terahertz quantum cascade lasers

Lander Gower,

Levy,

Piperno

et al. 2024

Journal of Vacuum Science &Amp; Technology B

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We hereby offer a comprehensive analysis of various factors that could potentially enable terahertz quantum cascade lasers (THz QCLs) to achieve room temperature performance. We thoroughly examine and integrate the latest findings from recent studies in the field. Our work goes beyond a mere analysis; it represents a nuanced and comprehensive exploration of the intricate factors influencing the performance of THz QCLs. Through a comprehensive and holistic approach, we propose novel insights that significantly contribute to advancing strategies for improving the temperature performance of THz QCLs. This all-encompassing perspective allows us not only to present a synthesis of existing knowledge but also to offer a fresh and nuanced strategy to improve the temperature performance of THz QCLs. We draw new conclusions from prior works, demonstrating that the key to enhancing THz QCL temperature performance involves not only optimizing interface quality but also strategically managing doping density, its spatial distribution, and profile. This is based on our results from different structures, such as two experimentally demonstrated devices: the spit-well resonant-phonon and the two-well injector direct-phonon schemes for THz QCLs, which allow efficient isolation of the laser levels from excited and continuum states. In these schemes, the doping profile has a setback that lessens the overlap of the doped region with the active laser states. Our work stands as a valuable resource for researchers seeking to gain a deeper understanding of the evolving landscape of THz technology. Furthermore, we present a novel strategy for future endeavors, providing an enhanced framework for continued exploration in this dynamic field. This strategy should pave the way to potentially reach higher temperatures than the latest records reached for Tmax of THz QCLs.

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THz Spectroscopy by Narrow Spectral Emission of Quantum Cascade Lasers for Medical Applications

Cited by 2 publications

References 37 publications

UHA‐CycleGAN: Unpaired hybrid attention network based on CycleGAN for terahertz image super‐resolution

UHA‐CycleGAN: Unpaired hybrid attention network based on CycleGAN for terahertz image super‐resolution

Doping engineering: Next step toward room temperature performance of terahertz quantum cascade lasers

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