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Ultra-wide tuning single channel filter based on one-dimensional photonic crystal with an air cavity

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Journal of Semiconductors 2017年第2期38卷 26-30页

作者： Xiaodan Zhao Yibiao Yang Zhihui Chen Yuncai Wang Hongming Fei Xiao Deng Department of Physics and Optoelectronics Taiyuan University of Technology Taiyuan 030024 China Key Laboratory of Advanced Transducers and Intelligent Control System Taiyuan University of TechnologyMinistry of Education Taiyuan 030024 China

By inserting an air cavity into a one-dimensional photonic crystal of LiF/GaSb, a tunable filter covering the whole visible range is proposed. Following consideration of the dispersion of the materials, through modulating the thickness of the air cavity, we demonstrate that a single resonant peak can shift from 416.1 to 667.3 nm in the band gap at normal incidence by means of the transfer matrix method. The research also shows that the transmittance of the channel can be maximized when the number of periodic Li F/Ga Sb layers on one side of the air defect layer is equal to that of the other side. When adding a period to both sides respectively, the full width at half maximum of the defect mode is reduced by one order of magnitude. This structure will provide a promising approach to fabricate practical tunable filters in the visible region with ultra-wide tuning range.

关键词： photonic crystal filters transfer matrix method single resonant peak ultra-wide tuning range mechanical modulation

Improving performance of organic photodetectors based on trap assisted photomultiplication through adjusting photogenerated carrier distributions

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arXiv 2018年

作者： Wang, Wenyan Shi, Linlin Zhang, Ye Hao, Yuying Zhu, Furong Wang, Kaiying Cui, Yanxia Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province College of Physics and Optoelectronics Taiyuan University of Technology Taiyuan030024 China Key Laboratory of Interface Science and Engineering in Advanced Materials Taiyuan University of Technology Taiyuan030024 China

Organic photodetectors (OPDs) based on trap-assisted photomultiplication (PM) effect with external quantum efficiency (EQE) far exceeding 100% are quite appealing for achieving highly sensitive photodetection. A classic structure of PM-type OPDs is based on the active layer of P3HT:PC70BM with the weight ratio of 100:1, in which PC70BM forms islands and supply bulk electron traps for inducing strong interfacial band bending and thus hole tunneling from the Al electrode. In this paper, aiming for optimizing the PM effect, we study the photogenerated carrier distribution by tuning thickness of the active layer (P3HT:PC70BM). The combination effect of both the exciton generation and exciton dissociation processes affects the photogenerated carrier distribution, which ultimately determines the PM performances of OPDs. On the one hand, simulation reveals that the thinner the active layer, the stronger exciton generation near the Al electrode. On the other hand, the photoluminescence and surface morphology studies reflect that the active layer with thickness of 230 nm has the smooth surface and produces the highest exciton dissociation rate. The two effects result in the OPD with a 205 nm thick active layer has the champion EQE (105569%) and photoresponsivity (344 A/W), corresponding to an enhancement of 330% with respect to the OPD with a 325 nm thick active layer. Ascribed to the trade off of EQE and dark current, the detectivity performs differently at different wavelength ranges. At short wavelength range, the detectivity reaches the highest when the active layer is 205 nm thick, while the highest detectivity at long wavelength range is produced by the thickest active layer. Our work contributes to developing low cost organic photodetectors for detecting weak light signals. Copyright © 2018, The Authors. All rights reserved.

关键词： Photons

Photon statistics and bunching of a chaotic semiconductor laser

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arXiv 2018年

作者： Yanqiang, G.U.O. Peng, Chunsheng Yulin, J.I. Pu, L.I. Yuanyuan, G.U.O. Xiaomin, G.U.O. Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province Taiyuan University of Technology Taiyuan030024 China Institute of Optoelectronic Engineering College of Physics and Optoelectronics Taiyuan University of Technology Taiyuan030024 China

The photon statistics and bunching of a semiconductor laser with external optical feedback are investigated experimentally and theoretically. In a chaotic regime, the photon number distribution is measured and undergoes a transition from Bose-Einstein distribution to Poisson distribution with increasing the mean photon number. The second order degree of coherence decreases gradually from 2 to 1. Based on Hanbury Brown-Twiss scheme, pronounced photon bunching is observed experimentally for various injection currents and feedback strengths, which indicates the randomness of the associated emission light. Near-threshold injection currents and strong feedback strengths modify exactly the laser performance to be more bunched. The macroscopic chaotic dynamics is confirmed simultaneously by high-speed analog detection. The theoretical results qualitatively agree with the experimental results. It is potentially useful to extract randomness and achieve desired entropy source for random number generator and imaging science by quantifying the control parameters. Copyright © 2018, The Authors. All rights reserved.

关键词： Random number generation

Enhancing quantum entropy in vacuum-based quantum random number generator

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arXiv 2018年

作者： Guo, Xiaomin Liu, Ripeng Li, Pu Cheng, Chen Wu, Mingchuan Guo, Yanqiang Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province Taiyuan University of Technology Taiyuan030024 China Institute of Optoelectronic Engineering College of Physics and Optoelectronics Taiyuan University of Technology Taiyuan030024 China

Information-theoretically provable unique true random numbers, which cannot be correlated or controlled by an attacker, can be generated based on quantum measurement of vacuum state and universal-hashing randomness extraction. Quantum entropy in the measurements decides the quality and security of the random number generator. At the same time, it directly determine the extraction ratio of true randomness from the raw data, in other words, it affects quantum random numbers generating rate obviously. In this work, considering the effects of classical noise, the best way to enhance quantum entropy in the vacuum-based quantum random number generator is explored in the optimum dynamical analog-digital converter (ADC) range scenario. The influence of classical noise excursion, which may be intrinsic to a system or deliberately induced by an eavesdropper, on the quantum entropy is derived. We propose enhancing local oscillator intensity rather than electrical gain for noise-independent amplification of quadrature fluctuation of vacuum state. Abundant quantum entropy is extractable from the raw data even when classical noise excursion is large. Experimentally, an extraction ratio of true randomness of 85.3% is achieved by finite enhancement of the local oscillator power when classical noise excursions of the raw data is obvious. Copyright © 2018, The Authors. All rights reserved.

关键词： Quantum theory

Detection of DNA Bases Using Fe Atoms and Graphene

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Chinese Physics Letters 2016年第1期33卷 123-126页

作者：胡建芬冯琳张文星李勇卢亚鑫 Key Laboratory of Advanced Transducers and Intelligent Control System(Ministry of Education) Department of PhysicsTaiyuan University of Technology

The adsorption of DNA bases on a magnetic probe composed of Fe atoms and graphene is studied by using first- principles calculations. The stability of geometry, the electronic structure and magnetic property are investigated. The results indicate that four DNA bases, i.e., adenine, thymine, cytosine and guanine, can all be adsorbed on the probe solidly. However, the magnetic moments of the composite structure can be observed only when adenine adsorbs on the probe. In the cases of the adsorption of the other three bases, the magnetic moments of the composite structure are zero. Based on the significant change of magnetic moment of the composite structure, adenine can be distinguished conveniently from thymine, cytosine and guanine. This work may provide a new way to detect DNA bases.

关键词： of on as in Fe Detection of DNA Bases Using Fe Atoms and Graphene that DNA is

A nanophotonic all-optical diode for non-reciprocal transmission of circularly polarized lights

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arXiv 2018年

作者： Fei, Hongming Wu, Min Lin, Han Liu, Xin Yang, Yibiao Zhang, Mingda Cao, Binzhao School of Physics and Optoelectronics Taiyuan University of Technology Taiyuan030024 China Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education Taiyuan University of Technology Taiyuan030024 China Micro-Photon Center Swinburne University of Technology 3122 Australia

All optical diodes (AODs) play an important role in quantum optics and information processing, in which the information is encoded by photons. Only circularly polarized lights are able to carry the spin states of photons, which has been intensively used in quantum computing and information processing and enable new research fields, such as chiral quantum optics. An ideal AOD should be able to work with arbitrary polarizations states, including circularly polarized lights, which has not been demonstrated yet. In this paper, we theoretically demonstrate for the first time a nanophotonic AOD that is able to work with circularly polarized lights. The AOD nanostructure is based on a heterostructure of two-dimension silica and silicon photonic crystals (PhCs). By controlling the effective refractive indices of the PhCs and using an inclined interface, we are able to exploit generalized total reflection principle to achieve non-reciprocal transmission of circularly polarized lights. In addition, the nanophotonic AOD is able to achieve high forward transmittance (>0.6) and high contrast ratio (~1) in a broad wavelength range (1497 nm～1666 nm). The designed nanophotonic AOD will find broad applications in optical quantum information processing and computing. Copyright © 2018, The Authors. All rights reserved.

关键词： Photonic crystals

Effects of incident energy and angle on carbon cluster ions implantation on silicon substrate:a molecular dynamics study

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Journal of Semiconductors 2017年第9期38卷 8-13页

作者： Ye Wei Shengbo Sang Bing Zhou Xiao Deng Jing Chai Jianlong Ji Yang Ge Yuanliang Huo Wendong Zhang Micro-Nano System Research Center Key Laboratory of Advanced Transducers and Intelligent Control SystemCollege of Information EngineeringTaiyuan University of TechnologyTaiyuan 030024China Research Institute of Surface Engineering Taiyuan University of TechnologyTaiyuan 030024China College of Physics and Optoelectronics Taiyuan University of TechnologyTaiyuan 030024China

Carbon cluster ion implantation is an important technique in fabricating functional devices at mi- cro/nanoscale. In this work, a numerical model is constructed for implantation and implemented with a cutting- edge molecular dynamics method. A series of simulations with varying incident energies and incident angles is performed for incidence on silicon substrate and correlated effects are compared in detail. Meanwhile, the behav- ior of the cluster during implantation is also examined under elevated temperatures. By mapping the nanoscopic morphology with variable parameters, numerical formalism is proposed to explain the different impacts on phrase transition and surface pattern formation. Particularly, implantation efficiency （IE） is computed and further used to evaluate the performance of the overall process. The calculated results could be properly adopted as the theoretical basis for designing nano-structures and adjusting devices＇ properties.

关键词： implantation low incident energies irradiation molecular dynamics

Flexible pulses from carbon nanotubes mode-locked fiber laser

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Chinese Physics B 2016年第12期25卷 258-261页

作者：杨玲珍杨义王娟芬 College of Physics and Optoelectronics Taiyuan University of Technology Laboratory of Advanced Transducers and Intelligent Control System Ministry of EducationTaiyuan University of Technology

We demonstrate a flexible erbium-doped pulsed fiber laser which achieves the wavelength and pulse width tuning by adjusting an intracavity filter. The intracavity filter is flexible to achieve any of the different wavelengths and bandwidths in the tuning range. The wavelength and width of pulse can be tuned in a range of - 20 nm and from - 0.8 ps to 87 ps, respectively. The flexible pulsed fiber laser can be accurately controlled, which is insensitive to environmental disturbance.

关键词： fiber laser mode-locked laser wavelength and pulse width tunable carbon nanotubes

A novel redundant flow matching steering principle for wheel loader

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A novel redundant flow matching steering principle for wheel...

第六届工程机械与车辆工程新进展国际学术会议

作者： Xiangyu Wang Jing Yang Long Quan Xiaogang Zhang Jun Wang Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi ProvinceTaiyuan University of Technology

The load sensing steering system of wheel loaders,driven by a constant displacement hydraulic pump,commonly leads to the large overflow and throttling loss during steering *** order to improve

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