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Enhancing Terahertz Circular Dichroism Spectrum of Amino Acid Chiral Enantiomers by All-Dielectric Metasurface

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SSRN

SSRN 2022年

作者： Zhang, Tianrui Liu, Jiayue Shi, Weinan Fan, Fei Chang, Shengjiang Institute of Modern Optics Nankai University Tianjin300350 China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin300350 China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Tianjin300350 China

The detection and identification of chiral substances have a wide range of applications, recently, using THz chiral spectroscopy to identify chiral biomolecules has attracted much attention. However, since the weak response, the difference between chiral enantiomers is not obvious only by THz chiral spectroscopy. To solve this problem, we combined THz time-domain polarization spectroscopy and all-dielectric metasurface to enhance the chiral spectroscopy of amino acids. The circular dichroism (CD) spectra of three pairs of amino acid chiral enantiomers were detected and compared by this method. Our results show that CD spectra of the amino acids are enhanced by the metasurface. L-Arg achieves a maximum chirality enhancement factor of 88.92 around 1 THz. For the recognition between L- and D- enantiomers, Cysteine has a maximum CD difference degree of 27.96°, which is 9.3 times higher than that without metasurface. Moreover, we also investigated the effect of amino acid concentration on chirality, founding that THz chirality was suppressed by high concentrations. Therefore, this metasurface sensor with the chiral sensing method has great potential in improving the THz chirality response of amino acids and distinguishing their chiral enantiomers with high sensitivity, which will provide new understanding and development in THz biophysics and biochemistry. © 2022, The Authors. All rights reserved.

关键词： Dichroism

Analysis of laser polarization state on remote induced plasma luminescence characteristics of filament in air

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arXiv 2023年

作者： Wang, Yuezheng Zhang, Zhi Zhang, Zeliang Zhang, Nan Lin, Lie Liu, Weiwei Institute of Modern Optics Eye Institute Nankai University Tianjin300350 China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Tianjin300350 China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin300350 China

The femtosecond laser filamentation is the result of the dynamic interplay between plasma self-focusing and defocusing generated by the multiphoton/tunnel ionization of air molecules. This equilibrium allows the filament to stably propagate over long distances at high power densities, making it a promising tool for remote sensing in chemical and biological applications, detection of air pollution, and lightning control, which has attracted wide attention. Laser-induced filamentation is a highly nonlinear process, and initial conditions such as changes in polarization state can affect the fluorescence emission of N2 molecules excited by the filament in air. In this article, we analyze in detail the effect of polarization state changes on the 337 nm fluorescence signal excited by the filament at a distance of 30 m. It was found that the fluorescence signal intensity of the linear polarization state was higher than that of the circular polarization state. Through analysis of these phenomena, we explore the mechanism of plasma fluorescence emission during the long-range filamentation process of femtosecond laser, including the electron collision model and the polarization effect on the critical power for filamentation. These findings are important for the understanding of the stimulated radiation from filaments and may find applications in remote sensing of electric field and THz radiation. Copyright © 2023, The Authors. All rights reserved.

关键词： Remote sensing

Femtosecond Laser Filamentation in Atmospheric Turbulence

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arXiv 2023年

作者： Guo, Jiewei Sun, Lu Wang, Yuezheng Xue, Jiayun Zhang, Zhi Liu, Haiyi Tao, Shishi Qi, Pengfei Lin, Lie Liu, Weiwei Institute of Modern Optics Eye Institute Nankai University Tianjin300350 China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Tianjin300350 China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin300350 China

The effects of turbulence intensity and turbulence region on the distribution of femtosecond laser filaments are experimentally elaborated. Through the ultrasonic signals emitted by the filaments, and it is observed that increasing turbulence intensity and expanding turbulence active region cause an increase in the start position of the filament, and a decrease in filament length, which can be well explained by the theoretical calculation. It is also observed that the random perturbation of the air refractive index caused by atmospheric turbulence expanded the spot size of the filament. Additionally, when turbulence intensity reaches 8.37 ×10−12 m−2/3 , multiple filaments are formed. Furthermore, the standard deviation of the transverse displacement of filament is found to be proportional to the square root of turbulent structure constant under the experimental turbulence parameters in this paper. These results contribute to the study of femtosecond laser propagation mechanisms in complex atmospheric turbulence conditions Copyright © 2023, The Authors. All rights reserved.

关键词： Atmospheric turbulence

Remote sensing of Trace Element in Sea Salt Aerosol with Sensitivity Level of 10 pg/m3

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arXiv 2023年

作者： Wang, Yuezheng Zhang, Nan Xue, Jiayun Shang, Bingpeng Guo, Jiewei Zhang, Zhi Qi, Pengfei Lin, Lie Liu, Weiwei Institute of Modern Optics Eye Institute Nankai University Tianjin300350 China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Tianjin300350 China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin300350 China

Sea salt aerosols composed mainly of micrometer-sized sodium chloride particles not only pose a potential threat to human health and traffic safety, but also directly affect climate prediction. The long-range and high-precision sensing of sea salt aerosols remains a challenge for existing composition analysis methods. As the development of ultrashort laser technology, femtosecond laser filamentation provides a new opportunity for molecular remote sensing in complex environments. However, the accuracy at long-distance of this method is still hard to meet the demand (3) for the remote aerosol monitoring. To solve this problem, we built a remote detection system for sea salt aerosol fluorescence spectroscopy and obtained a very high system sensitivity by introducing a terawatt-class high-performance femtosecond laser and optimizing the filament and aerosol interaction length. The system achieves a Na+ detection limit of 0.015 ng/m3 at a detection distance of 30 m, and 0.006 ng/m3 when supplemented with a deep processing learning algorithm. Copyright © 2023, The Authors. All rights reserved.

关键词： Fluorescence spectroscopy

Coupled air lasing gain and Mie scattering loss: aerosol effect in filament-induced plasma spectroscopy

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arXiv 2023年

作者： Xue, Jiayun Zhang, Zhi Wang, Yuezheng Shang, Binpeng Guo, Jiewei Tao, Shishi Zhang, Nan Lanjunguo Qi, Pengfei Lin, Lie Liu, Weiwei Institute of Modern Optics Eye Institute Nankai University Tianjin300350 China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Tianjin300350 China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin300350 China

Femtosecond laser filament-induced plasma spectroscopy (FIPS) demonstrates great potentials in the remote sensing for identifying atmospheric pollutant molecules. Due to the widespread aerosols in atmosphere, the remote detection based on FIPS would be affected from both the excitation and the propagation of fingerprint fluorescence, which still remain elusive. Here the physical model of filament-induced aerosol fluorescence is established to reveal the combined effect of Mie scattering and amplification spontaneous emission, which is then proved by the experimental results, the dependence of the backward fluorescence on the interaction length between filament and aerosols. These findings provide an insight into the complicated aerosol effect in the overall physical process of FIPS including propagation, excitation and emission, paving the way to its practical application in atmospheric remote sensing. Copyright © 2023, The Authors. All rights reserved.

关键词： Fluorescence

Filament based Ionizing Radiation sensing technology

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arXiv 2023年

作者： Liu, Weiwei Guo, Jiewei Zhang, Nan Sun, Lu Liu, Haiyi Tao, Shihi Wang, Yuezheng Shang, Binpeng Qi, Pengfei Lin, Lie Institute of Modern Optics Eye Institute Nankai University Tianjin300350 China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Tianjin300350 China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin300350 China

Accidental exposure to overdose ionizing radiation will inevitably lead to severe biological damage, thus detecting and localizing radiation is essential. Traditional measurement techniques are generally restricted to the limited detection range of few centimeters, posing a great risk to operators. The potential in remote sensing makes femtosecond laser filament technology great candidates for constructively address this challenge. Here we propose a novel filament-based ionizing radiation sensing technology (FIRST), and clarify the interaction mechanism between filaments and ionizing radiation. Specifically, it is demonstrated that the energetic electrons and ions produced by α radiation in air can be effectively accelerated within the filament, serving as seed electrons, which will markedly enhance nitrogen fluorescence. The extended nitrogen fluorescence lifetime of ~1 ns is also observed. These findings provide insights into the intricate interaction among ultra-strong light filed, plasma and energetic particle beam, and pave the way for the remote sensing of ionizing radiation. Copyright © 2023, The Authors. All rights reserved.

关键词： Ionizing radiation

On-Chip Photoelectric Hybrid Convolutional Accelerator Based on Bragg Grating Array

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SSRN

SSRN 2024年

作者： Cai, Kaiteng Chen, Liqi Zhang, Yunming Wang, Juncheng Lin, Wei Duan, Shaoxiang Liu, Bo Institute of Modern Optics Nankai University Tianjin300350 China Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology Nankai University Tianjin300350 China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Nankai University Tianjin300350 China

We propose an on-chip photoelectric hybrid convolution accelerator based on Bragg grating array. The weight of the convolution kernel can be adjusted by controlling the central wavelengths of the Bragg grating array. We conducted simulation verification of the functionality and scalability of this on-chip photoelectric hybrid convolution accelerator. Subsequently, we constructed a neural network model to conduct handwritten digit classification simulations using this accelerator, achieving a simulation accuracy of 93.99%. Finally, the concept of the proposed on-chip photoelectric hybrid convolution accelerator is successfully verified. Due to the merits of Bragg grating, the proposed scheme paves the way for realizing high-performance on-chip optical neural networks. © 2024, The Authors. All rights reserved.

关键词： Convolution

Magnetic ground state of CrOCl: A first-principles study

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Physical Review B 2023年第9期108卷 094435-094435页

作者： Haoran Zhu Peixuan Liu Xu Zuo Bin Shao College of Electronic Information and Optical Engineering Nankai University Tianjin 300350 China Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin Nankai University Tianjin 300350 China Engineering Research Center of Thin Film Optoelectronics Technology Ministry of Education Nankai University Tianjin 300350 China Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Nankai University Tianjin 300350 China

By first-principles calculations, this paper reveals that the antiferromagnetic (AFM) ground state of CrOCl with an orthorhombic structure observed in experiment is mainly due to the competition between the neighboring magnetic exchange interactions (Ji's). The AFM ground state requires that the first and second nearest neighbors (J1 and J2) are AFM couplings with comparable magnitudes, and that the seventh nearest neighbor (J7) has a certain size of AFM coupling. By using Liechtenstein's density functional theory (DFT+U) method and appropriately adjusting the on-site exchange (J) parameter, the Ji's can satisfy these conditions and lead to the experimentally observed AFM ground state (AFM-Exp). The J parameter changes the energy levels of the Cr-3d orbitals and consequently the energy differences between the orbitals, which in turn impacts the sign and magnitude of Ji's. By decomposing the Ji's into orbital contributions, it is shown that introducing the J parameter significantly reduces the ferromagnetic parts of J1 and J2 and converts them to AFM coupling, which leads to the AFM-Exp ground state.

关键词： Antiferromagnetism Exchange interaction Magnetism Layered crystals DFT+U Density functional calculations

Controlled on-chip fabrication of large-scale perovskite single crystal arrays for high-performance laser and photodetector integration

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Light(Science & Applications) 2023年第4期12卷 558-569页

作者： Zhangsheng Xu Xun Han Wenqiang Wu Fangtao Li Ru Wang Hui Lu Qiuchun Lu Binghui Ge Ningyan Cheng Xiaoyi Li Guangjie Yao Hao Hong Kaihui Liu Caofeng Pan CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijing 101400China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing 100049China College of Mechatronics and Control Engineering Shenzhen UniversityShenzhen 518060China Colllege of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Center on Nanoenergy Research School of Physical Science and TechnologyGuangxi UniversityNanning 530004China Information Materials and Intelligent Sensing Laboratory of Anhui Province Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationInstitutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China College of Materials Science and Engineering Ocean University of ChinaQingdao 266100China State Key Laboratory for Mesoscopic Physics Frontiers Science Centre for Nano-optoelectronicsSchool of PhysicsPeking UniversityBeijing 100871China Songshan Lake Materials Laboratory Dongguan 523808China

Metal halide perovskites possess intriguing optoelectronic properties,however,the lack of precise control of on-chip fabrication of the large-scale perovskite single crystal arrays restricts its application in integrated ***,we report a space confinement and antisolvent-assisted crystallization method for the homogeneous perovskite single crystal arrays spanning 100 square centimeter *** method enables precise control over the crystal arrays,including different array shapes and resolutions with less than 10%-pixel position variation,tunable pixel dimensions from 2 to 8 pm as well as the in-plane rotation of each *** crystal pixel could serve as a high-quality whispering gallery mode(WGM)microcavity with a quality factor of 2915 and a threshold of 4.14μJ cm^(-2).Through directly on-chip fabrication on the patterned electrodes,a vertical structured photodetector array is demonstrated with stable photoswitching behavior and the capability to image the input patterns,indicating the potential application in the integrated systems of this method.

关键词： arrays crystal precise