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Ellipticity control of high-order harmonic generation with nearly orthogonal two-color laser fields

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Physical Review A 2020年第5期101卷 053407-053407页

作者： Chunyang Zhai Renzhi Shao Pengfei Lan Bincheng Wang Yinfu Zhang Hua Yuan Stephen Maina Njoroge Lixin He Peixiang Lu Wuhan National Laboratory for Optoelectronics and School of Physics Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan 430205 China

Elliptically polarized high-order harmonics opens a path toward the study of ultrafast dynamics in circular dichroism of magnetic materials, chiral molecules, and electronic spin motion. Recently, efficient high-order harmonic generation with controllable ellipticity has attracted considerable attention in experiment and theory. Here, we experimentally demonstrate a scenario using cross-linearly-polarized two-color fields consisting of a fundamental field and its second harmonic (SH). Through adjusting the relative phase, crossing angle, and intensity ratio of the cross-linearly-polarized two-color field, we obtain ellipticity-tunable high-order harmonics, with ellipticity up to ɛ=0.73. Meanwhile, the elliptically polarized high-order harmonics preserve high efficiency. Furthermore, when the intensity of the SH field is stronger than that of the fundamental field, the even order harmonics will become several times stronger than the odd order harmonics with opposite helicity.

关键词： Strong field excitation Ultrafast optics

Plasmonic Nanoparticle-on-nanoslit Antenna as Independently Tunable Dual-Resonant Systems for Efficient Frequency Upconversion

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arXiv 2025年

作者： Hu, Huatian Hu, Zhiwei Galland, Christophe Chen, Wen State Key Laboratory of Precision Spectroscopy Science and Technology East China Normal University Shanghai200241 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China State Key Laboratory of Precision Spectroscopy Science and Technology East China Normal University China LausanneCH-1015 Switzerland

Dual-band plasmonic nanoantennas, exhibiting two widely separated user-defined resonances, are fundamental building blocks for the investigation and optimization of plasmon-enhanced optical phenomena, including photoluminescence, Raman scattering, and various nonlinear effects such as harmonic generation or sum-frequency generation, parametric down-conversion, etc. The nanoparticle-on-slit (NPoS) or nanoparticle-in-groove (NPiG) is a recently proposed dual-band antenna with independently tunable resonances at mid-infrared and visible wavelengths. It was used to enhance the corresponding sum- and difference-frequency generation processes from optimally located molecules by an estimated 1013-fold. However, the theoretical understanding of such structures and their eigenmodes remains poor, hindering further optimization and limiting broader applications. Here, we explore a diverse range of nanocavity-like quasinormal modes (QNMs) supported by NPoS structures, examining the contributions of both their near-field (i.e., giant photonic density of states) and far-field (i.e., spatial radiation patterns) characteristics to frequency upconversion. We identify methods for independently tuning the visible and mid-infrared resonances while conserving a good mode overlap in the near field, which is essential for efficient nonlinear processes. Moreover, through mode analysis, we unveil an experimentally unexplored fundamental resonance with greater field enhancement and much-improved mode overlap with the mid-infrared field, which could, in principle, further boost the mid-infrared upconversion efficiency by 5-fold compared to existing results. This work helps to rationalize and optimize the enhancement of nonlinear effects across a wide spectral range using a flexible and experimentally attractive nanoplasmonic platform. © 2025, CC BY.

关键词： Raman scattering

Robust convolutional neural network model for wavelength detection in overlapping fiber bragg grating sensor network

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Robust convolutional neural network model for wavelength det...

optical Fiber Communication Conference, OFC 2020

作者： Li, Baocheng Tan, Zhi-Wei Shum, Perry Ping Hu, Dora Juan Juan Wang, Chenlu Zheng, Yu Shuhui, Liu School of EEE Nanyang Technological University 50 Nanyang Avenue 639798 Singapore CINTRA CNRS NTU Thales UMI 3288 50 Nanyang Drive 637553 Singapore Singapore Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China

We have designed a CNN model to detect Bragg wavelengths in overlapping spectra. The mean RMS error of 0.123pm and mean testing time of 12.4ms are achieved, which outperforms most of the existing techniques. OFC 2020 ... 详细信息

ISBN: (数字)9781943580712

ISBN: (纸本)9781943580712

关键词： Sensor networks

Robust Convolutional Neural Network Model for Wavelength Detection in Overlapping Fiber Bragg Grating Sensor Network

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Robust Convolutional Neural Network Model for Wavelength Det...

2020 optical Fiber Communications Conference and Exhibition, OFC 2020

ISBN: (纸本)9781943580712

关键词： Sensor networks

Broadband-laser-diode pumped PPKTP-Sagnac polarization-entangled photon source

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arXiv 2021年

作者： Cai, Neng Cai, Wu-Hao Wang, Shun Li, Fang Shimizu, Ryosuke Jin, Rui-Bo Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China The University of Electro-Communications 1-5-1 Chofugaoka Tokyo Chofu Japan Guangdong Provincial Key Laboratory of Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China

We experimentally demonstrate a polarization-entangled photon source at 810 nm using a type-II phase-matched PPKTP crystal pumped by a low-cost, broadband laser diode with a central wavelength of 405 nm and a typical bandwidth of 0.53 nm. The PPKTP crystal is placed in a Sagnac-loop to realize the compact size and high stability. The downconverted biphotons, the signal and the idler, have typical bandwidths of 5.57 nm and 7.32 nm. We prepare two Bell states |Ψ+〉 and |Ψ−〉 with the fidelities of 0.948±0.004 and 0.963±0.002. In polarization correlation measurement, the visibilities are all higher than 96.2%, and in the Bell inequality test, the S value can achieve 2.78±0.01. This high-quality and low-cost entangled photon source may have many practical applications in quantum information processing. Copyright © 2021, The Authors. All rights reserved.

关键词： Photons

High-quality multi-wavelength quantum light sources on silicon nitride micro-ring chip

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arXiv 2022年

作者： Fan, Yun-Ru Lyu, Chen Yuan, Chen-Zhi Deng, Guang-Wei Zhou, Zhi-Yuan Geng, Yong Song, Hai-Zhi Wang, You Zhang, Yan-Feng Jin, Rui-Bo Zhou, Heng You, Li-Xing Guo, Guang-Can Zhou, Qiang Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China Chengdu610054 China CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China Key Lab of Optical Fiber Sensing and Communication Networks University of Electronic Science and Technology of China Chengdu611731 China Southwest Institute of Technical Physics Chengdu610041 China School of Electronics and Information Technology Sun Yat-sen University Guangzhou510275 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai200050 China

Multi-wavelength quantum light sources, especially at telecom band, are extremely desired in quantum information technology. Despite recent impressive advances, such a quantum light source with high quality remains challenging. Here we demonstrate a multi-wavelength quantum light source using a silicon nitride micro-ring with a free spectral range of 200 GHz. The generation of eight pairs of correlated photons is ensured in a wavelength range of 25.6 nm. With device optimization and noise-rejecting filters, our source enables the generation of heralded single-photons - at a rate of 62 kHz with gh(2)(0) = 0.014 ± 0.001, and the generation of energy-time entangled photons - with a visibility of 99.39 ± 0.45% in the Franson interferometer. These results, at room temperature and telecom wavelength, in a CMOS compatible platform, represent an important step towards integrated quantum light devices for the quantum networks. Copyright © 2022, The Authors. All rights reserved.

关键词： Light sources

Spatial-spectral mapping to prepare the frequency entangled qudits

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arXiv 2023年

作者： Yang, Zi-Xiang Zeng, Zi-Qi Tian, Ying Wang, Shun Shimizu, Ryosuke Wu, Hao-Yu Liu, Shilong Jin, Rui-Bo Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China The University of Electro-Communications 1-5-1 Chofugaoka Chofu Tokyo Japan Department of Physics University of Ottawa 25 Templeton Street ON OttawaK1N 6N5 Canada FemtoQ Lab Engineering Physics Department Polytechnique Montréal QC MontréalH3T 1JK Canada Guangdong Provincial Key Laboratory of Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China

Entangled qudits, the high-dimensional entangled states, play an important role in the study of quantum information. How to prepare entangled qudits in an efficient and easy-to-operate manner is still a challenge in quantum technology. Here, we demonstrate a method to engineer frequency entangled qudits in a spontaneous parametric downconversion process. The proposal employs an angle-dependent phase-matching condition in a nonlinear crystal, which forms a classical-quantum mapping between the spatial (pump) and spectral (biphotons) degrees of freedom. In particular, the pump profile is separated into several bins in the spatial domain, and thus shapes the down-converted biphotons into discrete frequency modes in the joint spectral space. Our approach provides a feasible and efficient method to prepare a high-dimensional frequency entangled state. As an experimental demonstration, we generate a three-dimensional entangled state by using a homemade variable slit mask. © 2023, CC BY.

关键词： Quantum entanglement

Spectrally resolved Franson interference

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arXiv 2023年

作者： Jin, Rui-Bo Zeng, Zi-Qi Xu, Dan Yuan, Chen-Zhi Li, Bai-Hong Wang, You Shimizu, Ryosuke Takeoka, Masahiro Fujiwara, Mikio Sasaki, Masahide Lu, Pei-Xiang Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China Department of Physics Shaanxi University of Science and Technology Xi’an710021 China Southwest Institute of Technical Physics Chengdu610041 China University of Electro-Communications 1-5-1 Chofugaoka Chofu Tokyo182-8585 Japan Keio University 3-14-1 Hiyoshi Kohoku Kanagawa Yokohama223-8522 Japan National Institute of Information and Communications Technology 4-2-1 Nukui-Kitamachi Koganei Tokyo184-8795 Japan

Franson interference can be used to test the nonlocal features of energy-time entanglement and has become a standard in quantum physics. However, most of the previous Franson interference experiments were demonstrated in the time domain, and the spectral properties of Franson interference have not been fully explored. Here, we theoretically and experimentally demonstrate spectrally resolved Franson interference using biphotons with different correlations, including positive correlation, negative correlation, and non-correlation. It is found that the joint spectral intensities of the biphotons can be modulated along both the signal and idler directions, which has potential applications in generating high-dimensional frequency entanglement and time-frequency grid states. This work may provide a new perspective for understanding the spectral-temporal properties of the Franson interferometer. © 2023, CC BY.

关键词： Quantum entanglement

A correction method for aero-optics thermal radiation effects based on gradient distribution and dark channel

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Optoelectronics Letters 2019年第5期15卷 374-380页

作者： HONG Han-yu SHI Yu ZHANG Tian-xu LIU Zhao Hubei Key Laboratory of Optical Information and Pattern Recognition Hubei Research Centre of Video Image and High Definition Projection School of Electrical and Information Engineering Wuhan Institute of Technology Wuhan 430074 China National Key Laboratory of Science and Technology on Multi-Spectral Information Processing School of Automation Huazhong University of Science and Technology Wuhan 430074 China

In this paper, a new algorithm is proposed to remove the effects of aerodynamic optical thermal radiation from a single infrared image. In this method, the joint probability model of gradient distribution is introduced by studying the "global smoothing and local fluctuation" characteristics of the bias field. A prior L0 norm of dark channel is introduced to constrain the latent clear image. Finally, the split Bregman method is used to solve the optimization problem. The effectiveness of the proposed method is verified by a series of experiments, and the results are compared with the results of the existing methods for the correction of thermal radiation effects.

关键词： aero-optics thermal radiation effects gradient distribution dark channel