检索结果-南通市图书馆

Dual bound states in the continuum enhanced second harmonic generation with Transition Metal Dichalcogenides monolayer

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Opto-Electronic Advances 2022年第7期5卷 10-15页

作者： Peilong Hong Lei Xu mohsen rahmani School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China(UESTC)Chengdu 611731China Advanced Optics&Photonics Laboratory Department of EngineeringSchool of Science&TechnologyNottingham Trent UniversityNottingham NG118NSUK.

This file includes:Section 1:Simulation methods Section 2:Field distribution of FW and SHW with homogeneous WS2 monolayer Section 3:Field distribution of FW and SHW with patterned WS2 monolayer Section 4:Asymmetric outcoupling rate of TE-type BIC Section 5:Quality factor of quasi-BIC for a finite size grating Section 6:A flow chart for designing the dual BICs scheme Section 7:TMDs monolayer orientation-dependent polarization-resolved SHG efficiency Section 8:SHG efficiency of homogeneous bulk GaP Section 9:Prospectives for experimental realizations Supplementary information for this paper is available at https://***/10.29026/oea.2022.200097.

关键词： Transition harmonic realization

Surface that perceives depth:3D imaging with metasurfaces

在线全文

学校读者我要写书评

暂无评论

Advanced Photonics 2019年第3期1卷 1-2页

作者： Lei Xu mohsen rahmani University of New South Wales School of Engineering and Information TechnologyCanberraAustralia The Australian National University Research School of Physics and EngineeringNonlinear Physics CentreCanberraAustralia

When Galileo Galilei(1564-1642)was building his super bulky lenses for telescopes,he could not imagine that 400 years later,metasurfaces,which are hundred times thinner than a human hair,1–3 could reproduce the function of his ***,for a few centuries,conventional bulky optics,such as lenses,prisms,mirrors,etc.,have been the only tools for shaping the wave-front of light via engineering the optical path of light beams through media of given refractive *** advances in nanofabrication,characterization,and computational optics techniques have enabled the development of ultrathin metasurfaces,composed of a single layer or few-layer stacks of periodic subwavelength nanostructures,that can reproduce the functions of bulk optics with better performance,4–6 and occasionally offer new functionalities that are not possible with conventional diffractive optics.

关键词： optics surfaces refractive

A noise cross PSD estimator for dual-microphone speech enhancement based on minimum statistics

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第6期10卷 805-809页

作者： mohsen rahmani Ahmad AKBARI Beghdad AYAD Nima DERAKHSHAN Research Center for Information Technology Computer DepartmentIran University of Science and Technology

Some two-microphone noise reduction techniques that work in the frequency domain exploit coherence function between two noisy signals. They have shown good results when noise signals on two sensors are uncorrelated, but their per-formance decreases with correlated noises. Coherence based methods can be improved when the cross power spectral density (CPSD) of correlated noise signals is available. In this paper, we propose a new method for estimation of the CPSD of the noise, which is based on the minimum tracking technique. Despite the fact that the proposed estimator does not need to implement a voice activity detector (VAD), its performance is comparable to a CPSD estimator that uses an ideal VAD.

关键词：麦克风估算私营部门语音噪音统计强基噪声信号

Bound states in the continuum in all-dielectric metasurfaces with scaled lattice constants

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2023年第12期66卷 101-109页

作者： Mimi Zhou Shaojun You Lei Xu Menghui Fan Jing Huang Wenbin Ma Mingzhe Hu Shengyun Luo mohsen rahmani Ya Cheng Lin Li Chaobiao Zhou Lujun Huang Andrey E.Miroshnichenko School of Physics and Mechatronic Engineering Guizhou Minzu UniversityGuiyang 550025China School of Chemical Engineering Guizhou Minzu UniversityGuiyang 550025China School of Materials Science and Engineering Guizhou Minzu UniversityGuiyang 550025China Advanced Optics and Photonics Laboratory Department of EngineeringSchool of Science TechnologyNottingham Trent UniversityNottingham NG118NSUK Extreme Optoelectromechanics Laboratory(XXL) School of Physics and Electronic SciencesEast China Normal UniversityShanghai 200241China State Key Laboratory of Precision Spectroscopy School of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China School of Engineering and Information Technology University of New South Wales at CanberraCanberra ACT 2610Australia

Bound states in the continuum(BICs)have emerged as an efficient tool for trapping light at the nanoscale,promising several exciting applications in *** the structural symmetry has been proposed as an effective way of exciting quasiBICs(QBICs)and generating high-Q ***,we demonstrate that QBICs can be excited in an all-dielectric metasurface by scaling the lattice of the metasurface,causing translational symmetry *** corresponding BICs arise from band folding from the band edge to the Γ point in the first Brillouin *** analysis reveals that the toroidal dipole dominates these ***,scaling the lattice along different directions provides additional freedom for tailoring QBICs,enabling polarization-dependent or-independent *** addition,this allows the realization of two QBICs at different wavelengths using plane-wave illumination with different polarizations on the *** experimentally demonstrated the existence of these BICs by fabricating silicon metasurfaces with scaled lattices and measuring their transmission *** vanished resonant linewidth identifies BICs in the transmission spectrum,and the QBICs are characterized by highQ Fano resonances with the Q-factor reaching *** results have potential applications in enhancing light-matter interaction,such as laser,nonlinear harmonic generation,and strong coupling.

关键词： lattice perturbation bound state in the continuum dielectric nanostructure

Third-harmonic generation and imaging with resonant Si membrane metasurface

在线全文

学校读者我要写书评

暂无评论

光电进展(英文) 2023年第8期6卷 18-27页

作者： Ze Zheng Lei Xu Lujun Huang Daria Smirnova Khosro Zangeneh Kamali Arman Yousefi Fu Deng Rocio Camacho-Morales Cuifeng Ying Andrey E.Miroshnichenko Dragomir N.Neshev mohsen rahmani Advanced Optics and Photonics Laboratory Department of EngineeringSchool of Science&TechnologyNottingham Trent UniversityNottingham NG118NSUK School of Engineering and Information Technology University of New South WalesCanberra ACT 2600Australia School of Physics and Electronic Science East China Normal UniversityShanghai 200241China ARC Centre of Excellence for Transformative Meta-Optical Systems(TMOS) Research School of PhysicsAustralian National UniversityCanberra ACT 2601Australia Department of Physics Hong Kong University of Science and TechnologyKowloonHong Kong SAR 999077China

Dielectric metasurfaces play an increasingly important role in enhancing optical nonlinear generations owing to their ability to support strong light-matter interactions based on Mie-type multipolar *** to metasurfaces composed of the periodic arrangement of nanoparticles,inverse,so-called,membrane metasurfaces offer unique possibilities for supporting multipolar resonances,while maintaining small unit cell size,large mode volume and high field enhancement for enhancing nonlinear frequency ***,we theoretically and experimentally investigate the formation of bound states in the continuum(BICs)from silicon dimer-hole membrane *** demonstrate that our BIC-formed resonance features a strong and tailorable electric near-field confinement inside the silicon membrane ***,we show that by tuning the gap between the holes,one can open a leaky channel to transform these regular BICs into quasi-BICs,which can be excited directly under normal plane wave *** prove the capabilities of such metasurfaces,we demonstrate the conversion of an infrared image to the visible range,based on the Third-harmonic generation(THG)process with the resonant membrane *** results suggest a new paradigm for realising efficient nonlinear photonics metadevices and hold promise for extending the applications of nonlinear structuring surfaces to new types of all-optical near-infrared imaging technologies.

关键词： nonlinear imaging third-harmonic generation bound states in the continuum membrane metasurfaces

Electrically programmable solid-state metasurfaces via flash localised heating

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2023年第3期12卷 391-397页

作者： Khosro Zangeneh Kamali Lei Xu Nikita Gagrani Hark Hoe Tan Chennupati Jagadish Andrey Miroshnichenko Dragomir Neshev mohsen rahmani ARC Centre of Excellence for Transformative Meta-Optical Systems(TMOS) Research School of PhysicsThe Australian National UniversityCanberraACT 2601Australia Advanced Optics and Photonics Laboratory Department of EngineeringSchool of Science and TechnologyNottingham Trent UniversityNottinghamNG118NSUK School of Engineering and Information Technology University of New South WalesCanberraACT 2600Australia

In the last decades,metasurfaces have attracted much attention because of their extraordinary light-scattering ***,their inherently static geometry is an obstacle to many applications where dynamic tunability in their optical behaviour is ***,there is a quest to enable dynamic tuning of metasurface properties,particularly with fast tuning rate,large modulation by small electrical signals,solid state and programmable across multiple ***,we demonstrate electrically tunable metasurfaces driven by thermo-optic effect and flash-heating in *** show a 9-fold change in transmission by<5 V biasing voltage and the modulation rise-time of<625µ*** device consists of a silicon hole array metasurface encapsulated by transparent conducting oxide as a localised *** allows for video frame rate optical switching over multiple pixels that can be electrically *** of the advantages of the proposed tuning method compared with other methods are the possibility to apply it for modulation in the visible and near-infrared region,large modulation depth,working at transmission regime,exhibiting low optical loss,low input voltage requirement,and operating with higher than video-rate switching *** device is furthermore compatible with modern electronic display technologies and could be ideal for personal electronic devices such as flat displays,virtual reality holography and light detection and ranging,where fast,solid-state and transparent optical switches are required.

关键词： tuning flash state

Pushing the limit of high-Q mode of a single dielectric nanocavity

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advanced Photonics 2021年第1期3卷 93-101页

作者： Lujun Huang Lei Xu mohsen rahmani Dragomir Neshev Andrey E.Miroshnichenko University of New South Wales School of Engineering and Information Technology Nottingham Trent University School of Science and Technology Department of Engineering Advanced Optics and Photonics Laboratory The Australia National University Research School of Physics Department of Electronic Material Engineering ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS)

High-index dielectric resonators support different types of resonant modes. However, it is challenging to achieve a high-Q factor in a single dielectric nanocavity due to the non-Hermitian property of the open system. We present a universal approach of finding out a series of high-Q resonant modes in a single nonspherical dielectric cavity with a rectangular cross section by exploring the quasi bound-state-in-thecontinuum(QBIC). Unlike conventional methods relying on heavy brutal force computations(i.e., frequency scanning by the finite difference time domain method), our approach is built upon Mie mode engineering,through which many high-Q modes can be easily achieved by constructing avoid-crossing(or crossing) of the eigenvalue for pair-leaky modes. The calculated Q-factor of mode TE(5,7) can be up to Qtheory=2.3 × 104for a freestanding square nanowire(NW)(n = 4), which is 64 times larger than the highest Q-factor(Qtheory≈ 360)reported so far in a single Si disk. Such high-Q modes can be attributed to suppressed radiation in the corresponding eigenchannels and simultaneously quenched electric(magnetic) field at momentum *** a proof of concept, we experimentally demonstrate the emergence of the high-Q resonant modes[Q ≈ 211 for mode TE(3,4), Q ≈ 380 for mode TE(3,5), and Q ≈ 294 for mode TM(3,5)] in the scattering spectrum of a single silicon NW.

关键词： Mie resonance leaky mode quasi bound state in the continuum high-Q mode dielectric nanocavity

Enhanced light-matter interactions in dielectric nanostructures via machine-learning approach

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Advanced Photonics 2020年第2期2卷 57-67页

作者： Lei Xu mohsen rahmani Yixuan Ma Daria ASmirnova Khosro Zangeneh Kamali Fu Deng Yan Kei Chiang Lujun Huang Haoyang Zhang Stephen Gould Dragomir N.Neshev Andrey E.Miroshnichenko University of New South Wales School of Engineering and Information TechnologyCanberraAustralia Nottingham Trent University School of Science&TechnologyDepartment of EngineeringAdvanced Optics and Photonics LaboratoryNottinghamUnited Kingdom Australian National University Research School of PhysicsNonlinear Physics CentreCanberraAustralia Australian National University Research School of PhysicsARC Centre of Excellence for Transformative Meta-Optical Systems(TMOS)CanberraAustralia Queensland University of Technology School of Electrical Engineering and Computer ScienceBrisbaneQueenslandAustralia Australian National University College of Engineering and Computer ScienceCanberraAustralia

A key concept underlying the specific functionalities of metasurfaces is the use of constituent components to shape the wavefront of the light on *** are versatile,novel platforms for manipulating the scattering,color,phase,or intensity of ***,one of the typical approaches for designing a metasurface is to optimize one or two variables among a vast number of fixed parameters,such as various materials’properties and coupling effects,as well as the geometrical ***,this would require multidimensional space optimization through direct numerical ***,an alternative,popular approach allows for reducing the computational cost significantly based on a deep-learning-assisted *** utilize a deep-learning approach for obtaining high-quality factor(high-Q)resonances with desired characteristics,such as linewidth,amplitude,and spectral *** exploit such high-Q resonances for enhancedlight–matter interaction in nonlinearoptical metasurfaces and optomechanical vibrations,*** demonstrate that optimized metasurfaces achieve up to 400-fold enhancement of the third-harmonic generation;at the same time,they also contribute to 100-fold enhancement of the amplitude of optomechanical *** approach can be further used to realize structures with unconventional scattering responses.

关键词： machine learning dielectric nanostructures Fano resonance third-harmonic generation optoacoustics

Infrared upconversion imaging in nonlinear metasurfaces

在线全文

学校读者我要写书评

暂无评论

Advanced Photonics 2021年第3期3卷 83-92页

作者： Rocio Camacho-Morales Davide Rocco Lei Xu Valerio Flavio Gili Nikolay Dimitrov Lyubomir Stoyanov Zhonghua Ma Andrei Komar Mykhaylo Lysevych Fouad Karouta Alexander Dreischuh Hark Hoe Tan Giuseppe Leo Costantino De Angelis Chennupati Jagadish Andrey E.Miroshnichenko mohsen rahmani Dragomir N.Neshev The Australian National University Research School of PhysicsARC Centre of Excellence for Transformative Meta-Optical SystemsDepartment of Electronic Materials EngineeringCanberraACTAustralia University of Brescia Department of Information EngineeringBresciaItaly University of New South Wales School of Engineering and Information TechnologyCanberraACTAustralia Nottingham Trent University School of Science and TechnologyAdvanced Optics and Photonics LaboratoryDepartment of EngineeringNottinghamUnited Kingdom UniversitéParis Diderot Matériaux et Phénomènes QuantiquesParisFrance Friedrich Schiller University Jena Institute of Applied PhysicsAbbe Center of PhotonicsJenaGermany Sofia University Department of Quantum ElectronicsFaculty of PhysicsSofiaBulgaria

Infrared imaging is a crucial technique in a multitude of applications,including night vision,autonomous vehicle navigation,optical tomography,and food quality *** infrared imaging technologies,however,require the use of materials such as narrow bandgap semiconductors,which are sensitive to thermal noise and often require cryogenic *** demonstrate a compact all-optical alternative to perform infrared imaging in a metasurface composed of GaAs semiconductor nanoantennas,using a nonlinear wave-mixing *** experimentally show the upconversion of short-wave infrared wavelengths via the coherent parametric process of sum-frequency *** this process,an infrared image of a target is mixed inside the metasurface with a strong pump beam,translating the image from the infrared to the visible in a nanoscale ultrathin imaging *** results open up new opportunities for the development of compact infrared imaging devices with applications in infrared vision and life sciences.

关键词： metasurfaces nonlinear optical processes infrared photonics imaging.