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arXiv 2022年

作者： Zhu, Jin-Long Zhu, Wen-Xin Shi, Xiao-Tao Zhang, Chen-Tao Hao, Xiangying Yang, Zi-Xiang Jin, Rui-Bo Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China

The mid-infrared (MIR) band entangled photon source is vital for the next generation of quantum communication, quantum imaging, and quantum sensing. However, the current entangled states are mainly prepared in visible or near-infrared bands. It is still lack of high-quality entangled photon sources in the MIR band. In this work, we optimize the poling sequence of lithium niobate to prepare two kinds of typical entangled states, the Hermit-Gaussian state and the comb-like entangled state at 3.2 µm. We have also calculated the photon pair rates and estimated the effect of fabrication resolution in the schemes. Our approach will provide entangled photon sources with excellent performance for the study of quantum information in the MIR band. © 2022, CC BY.

关键词： Quantum communication

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Compact ultra-broadband light coupling on chip via nonadiabatic pumping

arXiv

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arXiv 2024年

作者： Liu, Weiwei Li, Chijun Wang, Bing Chai, Tianyan Zheng, Lingzhi Liu, Zhuoxiong Zhang, Haoru Ren, Shuaifei Li, Xiaohong Zeng, Cheng Xia, Jinsong Lu, Peixiang Wuhan National Laboratory for Optoelectronics School of Physics Huazhong University of Science and Technology Wuhan430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China

Enlarging bandwidth capacity of the integrated photonic systems demands efficient and broadband light coupling among optical elements, which has been a vital issue in integrated photonics. Here, we have developed a compact ultra-broadband light coupling strategy based on nonadiabatic pumping in coupled optical waveguides, and experimentally demonstrated the designs in thin-film lithium niobate on insulator (LNOI) platform. We found that nonadiabatic transition would produce a decreased dispersion of the phases related to eigenstates in the waveguides. As a consequence, we realized high-efficiency directional transfer between edgestates for various wavelengths covering a 1-dB bandwidth of ∼320 nm in experiment (>400 nm in simulation), with a coupling length (∼50 μm) approximately 1/10 of that required in the adiabatic regime. Furthermore, we have constructed complex functional devices including beamsplitter and multiple-level cascaded networks for broadband light routing and splitting. Our work preserves significant advantages simultaneously in extending the operation bandwidth and minimizing the footprint, which demonstrates great potential for large-scale and compact photonic integration on chip. © 2024, CC BY-NC-ND.

关键词： Bandwidth

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Role of localized electronic states in high-order harmonic generation from doped semiconductors

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Physical Review B 2024年第16期109卷 165204-165204页

作者： Yuntian Zhang Wei He Liang Li Hubin Cui Sen Qiao Pengfei Lan Peixiang Lu School of Physics and Wuhan National Laboratory for Optoelectronics 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 CAS Center for Excellence in Ultra-intense Laser Science Shanghai 201800 China

We investigate high-order harmonic generation (HHG) in sparsely doped semiconductors. The doping in semiconductors breaks the periodic translation invariance in space and introduces localized electronic states (LESs), which leads to two additional electron transition channels, namely, the nonvertical transitions and transitions from LESs. By involving these channels, one can intuitively understand the enhancement of the harmonic yield and the extension of the cutoff energy found in previous works. Moreover, the transition from LESs is space localized and shows self-probed behavior under strong laser fields, encoding the structure information into the HHG. To demonstrate this, we analyze the HHG process in a doped semiconductor with a pair of impurities, where the recombination process of the electron from LESs can be interpreted as a two-center interference. This imprints the internuclear separation between the impurities into the minima of the harmonic spectra. Our work reveals the underlying physical mechanisms in HHG from doped semiconductors and suggests all-optical metrology for structural and dynamic information of LESs.

关键词： Electronic transitions High-order harmonic generation Doped semiconductors Solid state lasers Schroedinger equation

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Electron-wave-packet-deformation–induced attosecond emission time shift in gas high-order harmonic generation

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Physical Review A 2024年第2期109卷 023121-023121页

作者： Sen Qiao Liang Li Pengfei Lan 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 CAS Center for Excellence in Ultra-Intense Laser Science Shanghai 201800 China

The laser-induced recollision of electron trajectories is usually used to describe high-order harmonic generation (HHG), which also lays the foundation for high-order harmonic spectroscopy. Electron trajectory models based on the saddle-point approximation are conceptually similar to the light ray model in optics. Considering that ray optics is not complete to explain all wave optics phenomena, we revisit the validity of trajectory models when incorporating the Coulomb potential. Results show that, under commonly used gas HHG experimental conditions, both the classical three-step model and the quantum orbit model have dozens or hundreds of attoseconds of deviation in emission time. By using the Gaussian wave-packet method, we reveal that the time shift can be attributed to the deformation of the recollision electron wave packet. Wave-packet deformation is an inherent wavelike phenomenon caused by group delay dispersion and higher-order dispersion, and thereby is difficult to modify by particlelike trajectories. In addition, we reveal the notable influence of wave-packet deformation on observables in two-color field HHG experiments.

关键词： Atomic & molecular processes in external fields Strong-field-induced spectra XUV generation

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High-purity valley-polarized currents induced by bichromatic optical fields in two-dimensional materials

arXiv

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arXiv 2024年

作者： Li, Wenqing Zhu, Xiaosong Li, Liang He, Wanzhu Long, Jie Lan, Pengfei Lu, Peixiang Wuhan National Laboratory for Optoelectronics School of Physics Huazhong University of Science and Technology Wuhan430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China Hubei Optical Fundamental Research Center Wuhan430074 China

Producing currents predominantly from a single valley, namely valley-polarized currents, at optical-cycle timescales is an important aspect of the petahertz valleytronics, yet it remains less developed. This work exhibits the feasibility of achieving this goal using bichromatic optical fields, which allow for the precise control of sub-cycle electron dynamics. The combined effect of the helical and asymmetric waveforms of the optical fields leads to highly asymmetric excitation at different valleys and displacement of the excited electrons concurrently, thereby inducing valley-polarized currents with high valley purity, on the sub-optical-cycle timescale. Inherently, the purity of the currents built up from the optical approach remains high even for materials with short decoherence time. Moreover, the direction of the currents can be precisely controlled by adjusting the relative phase of the bichromatic components. Our work offers a promising avenue for generating and modulating high-purity valley-polarized currents at the femtosecond timescale, facilitating the development of petahertz valleytronics. Copyright © 2024, The Authors. All rights reserved.

关键词： Landforms

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Quasiparticle picture for high-harmonic generation in correlated electron systems

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Physical Review B 2023年第15期108卷 155125-155125页

作者： Kai Huang Tao-Yuan Du School of Mathematics and Physics China University of Geosciences Wuhan 430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan 430205 China Key Laboratory of Computational Physical Sciences (MOE) Fudan University Shanghai 200433 China

The key optical and electronic functionalities in condensed materials are determined by the band filling of electrons and their Coulomb correlations. To directly capture how many-body correlations influence the correlated electron dynamics under the driving of laser pulses, the comprehensible quasiparticle picture is desired to distinguish the ultrafast creation and annihilation of doublon-holon pairs in attosecond timescale. Here, we adopt the one-dimensional non-half-filling Hubbard model to study the high-harmonic generation (HHG) in correlated electron systems. As the value of Hubbard U increases, the cutoff energy and spectral features in HHG spectra have been revealed and their scaling laws are explained by the characteristic energy gaps obtained from the electronic bands under the quasiparticle picture. The adjustable degree of band filling in correlated systems paves a way to enhance high-harmonic emissions by regulating the creation of doublon-holon pairs. The complex temporal profile of HHG is elucidated in this work by the light-induced evolution of quasiparticle bands in correlated materials. In addition, the dephasing of the HHG spectrum caused by the vibration-induced disorder or lattice temperature is affirmed in the correlated electron systems and this dephasing process is attributed to quasiparticle-lattice scattering during the doublons and holons propagating among the disordered lattice sites.

关键词： High-order harmonic generation Strongly correlated systems Hubbard model Tight-binding model

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Solution-Processed Fe2-Xmgxo3 Ternary Oxides for Interface Passivation in Efficient Perovskite Solar Cells

SSRN

引用

SSRN 2022年

作者： Wang, Zhengchun Shi, Chang Wang, Ziyi Xiao, Lan Wu, Tong Pingli, Qin Yu, Xueli Ma, Liang Chen, Xiangbai Zhang, Jiliang School of Optical Information and Energy Engineering Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China

Interface function material has been widely used to reduce interfacial potential barrier for enhanced charge-dynamics and photovoltaic properties of perovskite solar cells (PSCs). Herein, ternary oxides Fe2-xMgxO3 are introduced to passivate the perovskite/SnO2 quantum dots (QDs) interface. The interaction between perovskite and Fe2-xMgxO3 could trigger a heterogeneous nucleation for the uniform perovskite photoactive layer. The flocculent Fe2-xMgxO3 also increase the interface contact with perovskite enabling more transferring channel of electron, and decrease the interface-defects with smaller the energy level offset at this interface. Such oxide bridges between perovskite and SnO2 QD could effectively enhance electron transfer. Consequently, a Fe1.84Mg0.16O3-based PSC is achieved with a champion efficiency over 21% and negligible J–V hysteresis. © 2022, The Authors. All rights reserved.

关键词： Nanocrystals

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High Capacitance of Ti3C2Tx Electrode Enabled by Nitrogen Doping and Surface Modification

SSRN

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SSRN 2024年

作者： Li, Haixia Yao, Yongyong Zhang, Xianghui Pan, Jing Tan, Lu Zhan, Chenwei Liu, Weifeng Feng, Yamin Xiong, Lun Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China Hubei Key Laboratory of Micro-Nanoelectronic Materials and Devices School of Microelectronics Hubei University Wuhan430062 China College of Physics and Telecommunication Engineering Zhoukou Normal University Zhoukou466001 China

Owing to its high electrical conductivity, unique layered structure, and strong hydrophilicity, two-dimensional titanium carbide (Ti3C2Tx) has attracted considerable attention as an electrode material for energy storage systems (EESs). However, applications of Ti3C2Tx to EESs are severely limited by self-restacking and –F surface terminations, which are usually inevitable during Ti3C2Tx preparation. To improve the electrochemical performance of Ti3C2Tx, the present authors doped Ti3C2Tx with nitrogen, preparing N–Ti3C2Tx, via thermal decomposition of urea. The interlayer spacing increased from 1.17 nm in Ti3C2Tx to 1.33 nm in N–Ti3C2Tx and the –F surface termination was largely reduced. Benefiting from the synergistic effect of modified surface termination and expanded interlayer spacing, the prepared N–Ti3C2Tx electrode in 1 M H2SO4 delivers a high specific capacitance (390 F g−1) at a current density of 1 A g−1 (approximately twice that of pristine Ti3C2Tx). To demonstrate the effectiveness of the method in other EESs, the Zn2+-storage capacity of the N–Ti3C2Tx electrode was tested in 1 M ZnSO4. The electrode exhibited a capacitance of 252 F g−1 at 1 A g−1, exceeding that of the pristine Ti3C2Tx electrode (212 F g−1). Furthermore, a supercapacitor, and a N–Ti3C2Tx//MnO2–CNTs system are fabricated using N–Ti3C2Tx, and it delivers a higher energy density and power density than the system with Ti3C2Tx electrode. The proposed strategy can facilely functionalize Ti3C2Tx for use in different high-performing EESs. © 2024, The Authors. All rights reserved.

关键词： Electrodes

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Helicity-dependent time delays in multiphoton ionization by two-color circularly polarized laser fields

引用

Frontiers of physics 2021年第5期16卷 3-9页

作者： Qing-Hua Ke Yue-Ming Zhou Yi-Jie Liao Jin-Tai Liang Yong Zhao Jia Tan Min Li Pei-Xiang Lu School of Physics and Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan430074China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of TechnologyWuhan430205China CAS Center for Excellence in Ultra-intense Laser Science Shanghai201800China

By numerically solving the three-dimensional time-dependent Schrödinger equation,we have investigated multiphoton ionization of hydrogen atom in the two-color circularly polarized(TCCP)laser fields consisting of a strong 400 nm and a much weaker 800 nm *** to the presence of perturbative 800 nm laser pulse,sideband peaks emerge between the above-threshold ionization rings in the photoelectron momentum *** numerical results show that the sideband peaks exhibit one-lobe structure in the co-rotating TCCP laser fields,while it displays the three-lobe structure in the counter-rotating TCCP laser ***,the photoelectron yield of sidebands in the co-rotating TCCP fields is much higher than those of the counter-rotating TCCP *** phenomena could be well explained from the perspective of the photon-absorption channels via the selection ***,an obvious phase shift between the sidebands of different orders from the co-rotating and counter-rotating TCCP fields is *** shift indicates the helicity-dependent time delay in the one-photon continuum-continuum transition process.

关键词： helicity-dependent time delay TCCP multiphoton ionization

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Controllable transitions among phase-matching conditions in a single nonlinear crystal

arXiv

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arXiv 2024年

作者： Zeng, Zi-Qi You, Shi-Xin Yang, Zi-Xiang Yuan, Chenzhi You, Chenglong Jin, Rui-Bo Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China Quantum Photonics Laboratory Department of Physics & Astronomy Louisiana State University Baton RougeLA70803 United States

Entangled photon pairs are crucial resources for quantum information processing protocols. Via the process of spontaneous parametric down-conversion (SPDC), we can generate these photon pairs using bulk nonlinear crystals. Traditionally, the crystal is designed to satisfy specific type of phase-matching condition. Here, we report controllable transitions among different types of phase-matching in a single periodically poled potassium titanyl phosphate (PPKTP) crystal. By carefully selecting pump conditions, we can satisfy different phase-matching conditions. This allows us to observe first-order type-II, fifth-order type-I, third-order type-0, and fifth-order type-II SPDCs. The temperature-dependent spectra of our source were also analyzed in detail. Finally, we discussed the possibility of observing more than nine SPDCs in this crystal. Our work not only deepens the understanding of the physics behind phase-matching conditions, but also offers the potential for a highly versatile entangled biphoton source for quantum information research. © 2024, CC BY.

关键词： Phase matching

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