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Atom interferometers with weak-measurement path detectors and their quantum mechanical analysis

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Chinese Physics B 2019年第6期28卷 45-65页

作者： zhi-yuan li College of Physics and Optoelectronics South China University of TechnologyGuangzhou 510641China

According to the orthodox interpretation of quantum physics, wave-particle duality(WPD) is the intrinsic property of all massive microscopic particles. All gedanken or realistic experiments based on atom interferometers(AI) have so far upheld the principle of WPD, either by the mechanism of the Heisenberg’s position-momentum uncertainty relation or by quantum entanglement. In this paper, we propose and make a systematic quantum mechanical analysis of several schemes of weak-measurement atom interferometer(WM-AI) and compare them with the historical schemes of strongmeasurement atom interferometer(SM-AI), such as Einstein’s recoiling slit and Feynman’s light microscope. As the critical part of these WM-AI setups, a weak-measurement path detector(WM-PD) deliberately interacting with the atomic internal electronic quantum states is designed and used to probe the which-path information of the atom, while only inducing negligible perturbation of the atomic center-of-mass motion. Another instrument that is used to directly interact with the atomic center-of-mass while being insensitive to the internal electronic quantum states is used to monitor the atomic centerof-mass interference pattern. Two typical schemes of WM-PD are considered. The first is the micromaser-cavity path detector, which allows us to probe the spontaneously emitted microwave photon from the incoming Rydberg atom in its excited electronic state and record unanimously the which-path information of the atom. The second is the optical-lattice Bragg-grating path detector, which can split the incoming atom beam into two different directions as determined by the internal electronic state and thus encode the which-path information of the atom into the internal states of the atom. We have used standard quantum mechanics to analyze the evolution of the atomic center-of-mass and internal electronic state wave function by directly solving Schr¨odinger’s equation for the composite atom-electron-photon system in the

关键词： wave-particle duality atom interferometers weak-measurement path-detector quantum entanglement Heisenberg’s uncertainty relation

Intense Two-Octave Ultraviolet-Visible-Infrared Supercontinuum Laser via High-Efficiency One-Octave Second-Harmonic Generation

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Research 2022年第4期2022卷 179-187页

作者： Mingzhou li lihong Hong zhi-yuan li School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510641China

Intense ultrabroadband laser source of high pulse energy has attracted more and more attention in physics,chemistry,biology,material science,and other *** report design and realization of a chirped periodically poled lithium niobate nonlinear crystal that supports ultrabroadband second-harmonic generation covering 350-850 nm by implementing simultaneously up to 12 orders of quasiphase matching against ultrabroadband pump laser covering 700-1700 nm with an average high conversion efficiency of about 25.8%.We obtain a flat supercontinuum spectrum with a 10 dB bandwidth covering more than one octave(about 375-1200 nm)and 20 dB bandwidth covering more than two octaves(about 350-1500 nm)in the ultraviolet-visible-infrared regime and having intense energy as 0.17 mJ per pulse through synergic action of second-order and third-order nonlinearity under pump of 0.48 mJ per pulse Ti:sapphire femtosecond *** scheme would provide a promising method for the construction of supercontinuum laser source with extremely broad bandwidth,large pulse energy,and high peak power for a variety of basic science and high technology applications.

关键词： pump Efficiency Infrared

Visible-near infrared ultra-broadband polarization-independent metamaterial perfect absorber involving phase-change materials

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Photonics Research 2016年第4期4卷 146-152页

作者： Ximin Tian zhi-yuan li Laboratory of Optical Physics Institute of Physics Chinese Academy of Science

We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge_2Sb_2Te_5(GST).The novel perfect absorber scheme consists of an array of high-index strong-absorbance GST square resonators separated from a continuous Au substrate by a low-index lossless dielectric layer(silica)and a high-index GST planar *** absorption peaks with the maximal absorbance up to 99.94% are achieved,owing to the excitation of plasmon-like dipolar or quadrupole resonances from the high-index GST resonators and cavity resonances generated by the GST planar *** intensities and positions of the absorption peaks show strong dependence on structural parameters.A heat transfer model is used to investigate the temporal variation of temperature within the GST *** results show that the temperature of amorphous GST can reach up to 433 K of the phase transition temperature from room temperature in just 0.37 ns with a relatively low incident light intensity of 1.11×10~8W∕m^2,due to the enhanced ultra-broadband light absorbance through strong plasmon resonances and cavity resonance in the *** study suggests a feasible means to lower the power requirements for photonic devices based on a thermal phase change via engineering ultra-broadband light absorbers.

关键词： MMPA Visible-near infrared ultra-broadband polarization-independent metamaterial perfect absorber involving phase-change materials GST

Quantum mechanical solution to spectral lineshape in strongly-coupled atom-nanocavity system

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Chinese Physics B 2022年第4期31卷 272-280页

作者： Jian Zeng zhi-yuan li School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510641China

The strongly coupled system composed of atoms,molecules,molecule aggregates,and semiconductor quantum dots embedded within an optical microcavity/nanocavity with high quality factor and/or low modal volume has become an excellent platform to study cavity quantum electrodynamics(CQED),where a prominent quantum effect called Rabi splitting can occur due to strong interaction of cavity-mode single-photon with the two-level atomic *** this paper,we build a new quantum model that can describe the optical response of the strongly-coupled system under the action of an external probing light and the spectral *** take the Hamiltonian for the strongly-coupled photon-atom system as the unperturbed Hamiltonian H_(0)and the interaction Hamiltonian of the probe light upon the coupled-system quantum states as the perturbed Hamiltonian *** theory yields a double Lorentzian lineshape for the permittivity function,which agrees well with experimental observation of Rabi splitting in terms of spectral *** quantum theory will pave the way to construct a complete understanding for the microscopic strongly-coupled system that will become an important element for quantum information processing,nano-optical integrated circuits,and polariton chemistry.

关键词： Rabi splitting nanocavity double Lorentzian lineshape

3D printing of plasmonic nanofocusing tip enabling high resolution,high throughput and high contrast optical near-field imaging

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light(Science & Applications) 2023年第10期12卷 2145-2153页

作者： li Long Qiurong Deng Rongtao Huang Jiafang li zhi-yuan li School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510641China School of Physics Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Luminescent Materials and Devices South China University of TechnologyGuangzhou 510640China

Scanning near-field optical microscopy(SNOM)offers a means to reach a fine spatial resolution down to~10 nm,but unfortunately suffers from low transmission efficiency of optical *** we present design and 3D printing of a fiber-bound polymer-core/gold-shell spiral-grating conical tip that allows for coupling the inner incident optical signal to the outer surface plasmon polariton with high efficiency,which then adiabatically transport,squeeze,and interfere constructively at the tip apex to form a plasmonic superfocusing spot with tiny size and high *** simulations and optical measurements show that this specially designed and fabricated tip has 10%transmission efficiency,~5 nm spatial resolution,20 dB signal-to-noise ratio,and 7000 pixels per second fast scanning *** high-resolution,high throughput,and high contrast SNOM would open up a new frontier of high spatial-temporal resolution detecting,imaging,and monitoring of single-molecule physical,chemical,and biological systems,and deepen our understanding of their basic science in the single-molecule level.

关键词： optical resolution printing

Topological photonic states in gyromagnetic photonic crystals:Physics,properties,and applications

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Chinese Physics B 2022年第11期31卷 1-11页

作者： Jianfeng Chen zhi-yuan li School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

Topological photonic states(TPSs)as a new type of waveguide state with one-way transport property can resist backscattering and are impervious to defects,disorders and metallic *** photonic crystal(GPC)is the first artificial microstructure to implement TPSs,and it is also one of the most important platforms for generating truly one-way TPSs and exploring their novel physical properties,transport phenomena,and advanced ***,we present a brief review of the fundamental physics,novel properties,and practical applications of TPSs based on *** first examine chiral one-way edge states existing in uniformly magnetized GPCs of ordered and disordered lattices,antichiral one-way edge states in cross magnetized GPCs,and robust one-way bulk states in heterogeneously magnetized ***,we discuss the strongly coupling effect between two co-propagating(or counter-propagating)TPSs and the resulting physical phenomena and device ***,we analyze the key issues and prospect the future development trends for TPSs in *** purpose of this brief review is to provide an overview of the main features of TPSs in GPC systems and offer a useful guidance and motivation for interested scientists and engineers working in related scientific and technological areas.

关键词： topological photonic states gyromagnetic photonic crystal one-way edge states

Kirigami/origami:unfolding the new regime of advanced 3D microfabrication/nanofabrication with“folding”

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light(Science & Applications) 2020年第1期9卷 1309-1327页

作者： Shanshan Chen Jianfeng Chen Xiangdong Zhang zhi-yuan li Jiafang li Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement(Ministry of Education) Beijing Key Lab of Nanophotonics&Ultrafine Optoelectronic Systemsand School of PhysicsBeijing Institute of Technology100081 BeijingChina College of Physics and Optoelectronics South China University of Technology510640 GuangzhouChina

Advanced kirigami/origami provides an automated technique for modulating the mechanical,electrical,magnetic and optical properties of existing materials,with remarkable flexibility,diversity,functionality,generality,and *** this paper,we review the latest progress in kirigami/origami on the microscale/nanoscale as a new platform for advanced 3D microfabrication/*** stimuli of kirigami/origami,including capillary forces,residual stress,mechanical stress,responsive forces,and focussed-ion-beam irradiation-induced stress,are introduced in the microscale/nanoscale *** stimuli enable direct 2D-to-3D transformations through folding,bending,and twisting of microstructures/nanostructures,with which the occupied spatial volume can vary by several orders of magnitude compared to the 2D *** an instant and direct method,ion-beam irradiation-based tree-type and close-loop nano-kirigami is highlighted in *** progress in microscale/nanoscale kirigami/origami for reshaping the emerging 2D materials,as well as the potential for biological,optical and reconfigurable applications,is briefly *** the unprecedented physical characteristics and applicable functionalities generated by kirigami/origami,a wide range of applications in the fields of optics,physics,biology,chemistry and engineering can be envisioned.

关键词： regime folding enable

Level density of odd-A nuclei at saddle point

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Nuclear Science and Techniques 2023年第8期34卷 164-173页

作者： Wei Zhang Wei Gao Gui-Tao Zhang zhi-yuan li School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China

Based on the covariant density functional theory,by employing the core–quasiparticle coupling(CQC)model,the nuclear level density of odd-A nuclei at the saddle point is *** total level density is calculated via the convolution of the intrinsic level density and the collective level *** intrinsic level densities are obtained in the finite-temperature covariant density functional theory,which takes into account the nuclear deformation and pairing *** saddle points on the free energy surface in the(β_(2),γ)plane,the entropy and the associated intrinsic level density are compared with those of the global *** introducing a quasiparticle to the two neighboring even–even core nuclei,whose properties are determined by the five-dimensional collective Hamiltonian model,the collective levels of the odd-A nuclei are obtained via the CQC *** total level densities of the^(234-240)U agree well with the available experimental data and Hilaire’s ***,the ratio of the total level densities at the saddle points to those at the global minima and the ratio of the total level densities to the intrinsic level densities are discussed separately.

关键词： Level density Covariant density functional theory Core–quasiparticle coupling model Saddle point

Optical forces exerted on a graphene-coated dielectric particle by a focused Gaussian beam

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Photonics Research 2016年第2期4卷 65-69页

作者： Yang Yang Zhe Shi Jiafang li zhi-yuan li Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Key Laboratory of Micro-Nano Measurement-Manipulation and Physics (Ministry of Education) Beihang University

In this paper, we derive the analytical expression for the multipole expansion coefficients of scattering and interior fields of a graphene-coated dielectric particle under the illumination of an arbitrary optical beam. By using this arbitrary beam theory, we systematically investigate the optical forces exerted on the graphene-coated particle by a focused Gaussian beam. Via tuning the chemical potential of the graphene, the optical force spectra could be modulated accordingly at resonant excitation. The hybridized whispering gallery mode of the electromagnetic field inside the graphene-coated polystyrene particle is more intensively localized than the pure polystyrene particle, which leads to a weakened morphology-dependent resonance in the optical forces. These investigations could open new perspectives for dynamic engineering of optical manipulations in optical tweezers applications.

关键词： Optical forces exerted on a graphene-coated dielectric particle by a focused Gaussian beam