Frequency-tunable single-photon router based on a microresonator containing a driven three-level emitter

We propose a frequency-tunable router of single photons with high routing efficiency, which is constructed by two waveguides mediately linked by a single-mode whispering gallery resonator with a driven three-level emitter. Quantum routing probability in the output port is obtained via the real-space Hamiltonian. By adjusting the resonator–emitter coupling and the drive, the desired continuous central frequencies for the resonance peaks of routing photons can be manipulated nearly linearly, with the assistance of Rabi splitting effect and optical Stark shift. The proposed routing system may provide potential applications in designing other frequency-modulation quantum optical devices, such as multiplexers,filters, and so on.

Tunable Multichannel Quantum Routing of Single Photons Based on Single-Mode Microresonators

We have suggested a novel multiport quantum router of single photons with reflection feedback, which is formed by three waveguides coupled with four single-mode microresonators. The single-photon routing probabilities of four channels in the coupled system are studied theoretically by applying the real-space approach. Numerical results indicate that unidirectional routing in these output channels can be effectively implemented, and the router is tunable to route desired frequencies into the output ports, by varying the inter-resonator detunings via spinning resonator technology. Therefore, the proposed multichannel system can provide potential applications in optical quantum communication.

Sensing and lasing applications of whispering gallery mode microresonators

Optical whispering gallery mode （WGM） microresonators have attracted great attention due to their remarkable proper- ties such as extremely high quality factor, small mode volume, tight confinement of modes, and strong evanescent field. All these properties of WGM microresonators have ensured their great potentials for applications, such as physical sen- sors, bio/chemical sensors and microlasers. In this mini-review, the key parameters and coupling conditions of WGM microresonators are firstly introduced. The geometries of WGM optical microcavities are presented based on their fabri- cation methods. This is followed by the discussion on the state-of-the-art applications of WGM microresonators in sen- sors and microlasers.

Insulin producing cells established using non-integrated lentiviral vector harboring PDX1 gene

AIM: To investigate reprogramming of human adipose tissue derived stem cells into insulin producing cells using non-integrated lentivirus harboring PDX1 gene.METHODS: In this study, human adipose tissue derived stem cells(hADSCs) were obtained from abdominal adipose tissues by liposuction, selected by plastic adhesion, and characterized by flow cytometric analysis.Human ADSCs were differentiated into adipocytes and osteocytes using differentiating medium to confirm their multipotency. Non-integrated lentiviruses harboring PDX1(Non-integrated LV-PDX1) were constructed using specific plasmids(pLV-HELP, pMD2G, LV-105-PDX1-1).Then, hADSCs were transduced with non-integrated LVPDX1. After transduction, ADSCsPDX1+were cultured in high glucose DMEM medium supplement by B27, nicotinamide and βFGF for 21 d. Expressions of PDX1 andinsulin were detected at protein level by immunofluorescence analysis. Expressions of PDX1, neurogenin3(Ngn3), glucagon, glucose transporter2(Glut2) and somatostatin as specific marker genes were investigated at mRNA level by quantitative RT-PCR. Insulin secretion of hADSCsPDX1+in the high-glucose medium was detected by electrochemiluminescence test. Human ADSCsPDX1+were implanted into hyperglycemic rats.RESULTS: Human ADSCs exhibited their fibroblast-like morphology and made colonies after 7-10 d of culture.Determination of hADSCs identified by FACS analysis showed that hADSCs were positive for mesenchymal cell markers and negative for hematopoietic cell markers that guaranteed the lack of hematopoietic contamination. In vitro differentiation of hADSCs into osteocytes and adipocytes were detected by Alizarin red and Oil red O staining and confirmed their multilineage differentiation ability. Transduced hADSCs+PDX1became round and clusters in the differentiation medium. The appropriate expression of PDX1 and insulin proteins was confirmed using immunocytochemistry analysis.Significant expressions of PDX1, Ngn3, glucagon, Glut2and somatostatin were detected by quantitative RTPCR. hADSCsPDX1+revealed the glucose sensing ability by expressing Glut2 when they were cultured in the medium containing high glucose concentration. The insulin secretion of hADSCsPDX1+in the high glucose medium was 2.32 μU/mL. hADSCsPDX1+implantation into hyperglycemic rats cured it two days after injection by reducing blood glucose levels from 485 mg/dL to the normal level.CONCLUSION: Human ADSCs can differentiate into IPCs by non-integrated LV-PDX1 transduction and have the potential to be used as a resource in type 1 diabetes cell therapy.

Rational design of thermoelastic damping in microresonators with phase-lagging heat conduction law

The design of thermoelastic damping(TED)affected by the phase-lagging non-Fourier heat conduction effects becomes significant but challenging for enlarging the quality factor of widely-used microresonators operating in extreme situations,including ultra-high excitation frequency and ultra-low working temperature.However,there does not exist a rational method for designing the TED in the framework of non-Fourier heat conduction law.This work,therefore,proposes a design framework to achieve low thermoelastic dissipation of microresonators governed by the phase-lagging heat conduction law.The equation of motion and the heat conduction equation for phase-lagging TED microresonators are derived first,and then the non-Fourier TED design problem is proposed.A topology optimization-based rational design method is used to resolve the design problem.What is more,a two-dimensional(2D)plain-strain-based finite element method(FEM)is developed as a solver for the topology optimization process.Based on the suggested rational design technique,numerical instances with various phase lags are investigated.The results show that the proposed design method can remarkably reduce the dissipation of microresonators by tailoring their substructures.

EFFECT OF ELECTROSTATIC RESISTANCE ON THE SHUTTLE OF MICRORESONATOR

To improve the performance and reliability of microelectromechanical system＇s devices, it is necessary to understand the effect of friction which exists in the majority of microelectromechanical systems （MEMS） with a large ratio of surface area to their volume. The model of electrostatic tangential force of the shuttle in laterally driven comb microresonator is established based on the rule of energy conservation. The effects of microscale, surface roughness, applied voltage, and micro asperities or dents or holes formed in fabrication are investigated, and the electrostatic resistance between two charged moving plates is analyzed. The analytic results are coincident well with those of ANSYS simulation. It is found that the electrostatic resistance becomes high as the increase of the ratio of the shuttle width to the gap between moving plates and the relative surface roughness or the increment of the applied voltage.

Fabrication of microresonators by using photoresist developer as etchant

In superconducting circuit,microwave resonators and capacitors are crucial components,and their quality has a strong impact on circuit performance.Here we develop a novel wet etching process to define these two components using common photoresist developer as etchant.This method reduces subsequent steps and can be completed immediately after development.By measuring the internal quality factor of resonators,we show that it is possible to achieve similar or better performance when compared with samples made by standard etching processes.This easy-to-implement method may boost the yield hence providing an alternative fabrication process for microwave resonators and capacitors.

Effects of Resonator Loss on Output Characteristics of Ring Microresonator Filter

The ring microresonator filter considering resonator inner loss is analyzed theoretically, which has one input port and two output ports. Some universal relations for coupling of optical power between microresonator and dielectric waveguides are presented. The analytical expressions of filter bandwidth or the full width at half maximum(FWHM), free spectral range and finesse of resonator are derived. The characteristics of the ring microresonator filter are discussed numerically. It is demonstrated that the loss of the ring resonator reduces the peak value of transmission, widens the filter bandwidth, and reduces the finesse of the resonator filter.

A 4 MHz Lamé mode microresonator-based oscil lator

A 4.13 MHz reference oscillator incorporating a capacitive single-crystal-silicon （SCS） micromechanical resonator is presented. The microresonator is fabricated using a cavity silicon-on-insulator （cavity-SOl） process and is excited in the Lain6 mode with electrostatic driving and capacitive sensing. The Lam6 mode may be described as a square plate that is cont- racting along one axis in the fabrication plane, while simultaneously extending along an orthogonal axis in the same plane. The microresonator exhibits a quality factor as high as 1.4 × 10^6 and a resonant frequency of 4.13 MHz at a pressure of 0.08 mbar. The output spectrum of the oscillator shows that the silicon micromechanical resonator is adapted as a timing element for a precision oscillator.

基于双频泵浦正常色散碳化硅微环谐振腔的光频率梳设计

提出一种利用锁相双频激光泵浦正常色散碳化硅微环谐振腔产生光频率梳的方案.对绝缘体上碳化硅微环谐振腔光波导进行色散调控,实现1550 nm波段平坦正常色散优化设计.利用Lugiato-Lefever方程对锁相双频激光泵浦正常色散碳化硅微环谐振腔的光频率梳产生进行仿真,研究了泵浦失谐量改变时光频率梳产生的时域和频域演化过程.同时探究了泵浦功率、微腔波导损耗、微腔色散、双频激光功率占比、双频激光频率间隔等各项参数对光频率梳产生的影响,仿真产生的光频率梳带宽可覆盖1500—1600 nm.仿真结果有助于推动基于正常色散碳化硅微环谐振腔的1550 nm波段高重复频率宽带光频率梳的研究和应用.

氟化镁微瓶腔光频梳光谱分析及优化

氟化镁微腔光频梳具有体积小、功耗低、光谱覆盖范围广、色散可调控的优势,在光通信、中红外光谱等领域有着潜在应用前景.本文研究了氟化镁回音壁模式微瓶腔平台产生的光频梳光谱特性.为了优化氟化镁微瓶腔光频梳的光谱分布,利用有限元法迭代求解了瓶腔结构在不同曲率和轴向模式下的二阶色散及高阶色散,通过分步傅里叶法求解非线性薛定谔方程仿真了不同轴向模式激励下的光频梳光谱演变过程.结果表明,在最佳曲率半径下通过低阶轴向模式激励可以实现宽带范围的近零反常色散调谐,而高阶轴向模式将导致微瓶腔呈现弱正常色散.在低阶轴向模式下较弱的反常色散使光频梳的带宽得到展宽,证明了三阶色散和负的四阶色散可以展宽克尔孤子光频梳;在高阶轴向模式下弱正常色散抑制了克尔光频梳的产生,拉曼光频梳占主导地位.在适宜的泵浦条件下通过调控微瓶腔的轴向模式可以实现克尔孤子光频梳和拉曼光频梳的选择性激发.本文工作的开展将为氟化镁微腔色散设计及宽带克尔孤子光频梳、拉曼光频梳实验调控提供指导意义.

非集成微腔中的光学频率梳研究进展(特邀)

光学频率梳在频域上是一系列离散的、等间隔的、具有稳定相位关系的谱线,光谱覆盖范围可达百太赫兹量级,被称为光学标尺,它的出现显著提高了时间与频率的测量精度,其重要性得到了广泛认可,该领域科学家也因此获得了2005年诺贝尔物理学奖。早期的光频梳系统由固态锁模激光器构成,系统复杂且体积庞大。近年来,新兴的微腔光频梳以小型化、低功耗、相对简易的产生系统等优势极大促进了光频梳技术的发展。由于制备相对简单,且具有超高的品质因子和丰富的模式族,非片上集成的光学微腔为克尔光频梳提供了更为便利的研究平台,进一步拓展了克尔光频梳的应用场景。本文介绍了微腔光频梳的理论模型,描述了微腔光频梳的产生过程与产生方式,梳理了克尔光频梳在各类非集成微腔中的研究进展,展示了非集成微腔光梳的应用场景,总结了目前非集成微腔光梳研究所面临的挑战,并对该领域未来的研究趋势进行了展望。

Harnessing sub-comb dynamics in a graphene-sensitized microresonator for gas detection

Since their inception, frequency combs generated in microresonators, known as microcombs, have sparked significant scientific interests. Among the various applications leveraging microcombs, soliton microcombs are often preferred due to their inherent mode-locking capability. However, this choice introduces additional system complexity because an initialization process is required. Meanwhile, despite the theoretical understanding of the dynamics of other comb states, their practical potential, particularly in applications like sensing where simplicity is valued, remains largely untapped. Here, we demonstrate controllable generation of sub-combs that bypasses the need for accessing bistable regime. And in a graphene-sensitized microresonator, the sub-comb heterodynes produce stable, accurate microwave signals for high-precision gas detection. By exploring the formation dynamics of sub-combs, we achieved 2 MHz harmonic comb-to-comb beat notes with a signal-to-noise ratio (SNR) greater than 50 dB and phase noise as low as – 82 dBc/Hz at 1 MHz offset. The graphene sensitization on the intracavity probes results in exceptional frequency responsiveness to the adsorption of gas molecules on the graphene of microcavity surface, enabling detect limits down to the parts per billion (ppb) level. This synergy between graphene and sub-comb formation dynamics in a microcavity structure showcases the feasibility of utilizing microcombs in an incoherent state prior to soliton locking. It may mark a significant step toward the development of easy-to-operate, systemically simple, compact, and high-performance photonic sensors.

Soliton microcomb generation by cavity polygon modes

Soliton microcombs,which require the hosting cavity to operate in an anomalous dispersion regime,are essential to integrate photonic systems.In the past,soliton microcombs were generated on cavity whispering gallery modes(WGMs),and the anomalous dispersion requirement of the cavity made by normal dispersion material was achieved through structural dispersion engineering.This inevitably degrades the cavity optical quality factor(Q)and increases pump threshold power for soliton comb generation.To overcome the challenges,here,we report a soliton microcomb excited by cavity polygon modes.These modes display anomalous dispersion at near-infrared while optical Q factors exceeding 4×10^(6) are maintained.Consequently,a soliton comb spanning from 1450 nm to 1620 nm with a record low pump power of 11 m W is demonstrated,a three-fold improvement compared to the state of the art on the same material platform.

Reversible generation of dissipative Kerr solitons in a microresonator by the backward tuning method

Soliton generation schemes have attracted considerable scholarly attention.This paper introduces a novel backward tuning method for the reversible generation of dissipative Kerr solitons(DKSs).Reversible soliton generation relies on the thermal stabilization of the auxiliary laser,coupled with backward tuning of the pump laser,significantly increasing the range of soliton steps by over 10 times.Moreover,the method alleviates the stringent auxiliary laser detuning requirement.By adjusting the detuning of the auxiliary laser,diverse numbers of solitons can be deterministically generated,enhancing both flexibility and precision.

FIRST-PASSAGE TIME OF QUASI-NON-INTEGRABLE-HAMILTONIAN SYSTEM

Studies on first-passage failure are extended to the multi-degree-of-freedom quasi-non-integrable-Hamiltonian systems under parametric excitations of Gaussian white noises in this paper. By the stochastic averaging method of energy envelope, the system's energy can be modeled as a one-dimensional approximate diffusion process by which the classical Pontryagin equation with suitable boundary conditions is applicable to analyzing the statistical moments of the first-passage time of an arbitrary order. An example is studied in detail and some numerical results are given to illustrate the above procedure.

STOCHASTIC OPTIMAL CONTROL FOR THE RESPONSE OF QUASI NON-INTEGRABLE HAMILTONIAN SYSTEMS

A strategy is proposed based on the stochastic averaging method for quasi non- integrable Hamiltonian systems and the stochastic dynamical programming principle.The pro- posed strategy can be used to design nonlinear stochastic optimal control to minimize the response of quasi non-integrable Hamiltonian systems subject to Gaussian white noise excitation.By using the stochastic averaging method for quasi non-integrable Hamiltonian systems the equations of motion of a controlled quasi non-integrable Hamiltonian system is reduced to a one-dimensional av- eraged It stochastic differential equation.By using the stochastic dynamical programming princi- ple the dynamical programming equation for minimizing the response of the system is formulated. The optimal control law is derived from the dynamical programming equation and the bounded control constraints.The response of optimally controlled systems is predicted through solving the FPK equation associated with It stochastic differential equation.An example is worked out in detail to illustrate the application of the control strategy proposed.

Non-integrable Movement Equations in Landsliding System

The answer of the question was considered as non-integrable basically. The integrable system was thought in the exceptional.Since Poincare had presented in a theorem and proved that non-integrable system is normal, and yet integrable system is abuormal. In the landsliding system, discussed question was regarded to be true.Sortie fundamentals were considered; other systems and example with engineering control are concerned and discussed in details.

On the Differential Formulas for Singular Integrals of High Non-Integral Order

When kernel density is in the class of continuous function to possessing sufficient derivative of high order(and needn't in the class of corresponding Holder function),in this paper it is given the continuity and the differential formulas for singular integrals of high non--integral order. The above results themselves and in order to prove in future the formulas to changing order of integration for singular integrals of high non-integral order(another paper) will have important significance. The method to prove in this paper is more different from the method in the corresponding cass of singular integrals of high integral order.

微腔光梳的产生、发展及应用

光频梳提供了光波和微波相干链接的桥梁,它的诞生革命性地提高了人们对于光学频率和时间的测量精度,深刻影响着当今世界科技的发展.最早的光频梳产生于锁模激光器系统,然而基于锁模激光器的光梳,因其系统复杂、体积庞大和价格高昂,一般仅限于实验室应用.近年来一种新型光频梳应运而生,并有望解决上述问题.它是通过连续激光耦合进入高品质光学微腔而激发的,在频域上通过四波混频产生等间距的频率分量,在时域上则利用非线性效应平衡微腔色散而形成锁模,这种新型光频梳被称为“微腔光梳”.相比于传统光梳,微腔光梳有着尺寸小、可集成、功耗低和重频范围大等优势,它的出现标志着产生光梳迈向芯片级尺寸的时代,并引起了科学界和工业界越来越多的关注.本文首先概述了微腔光梳的产生与发展历程,随后介绍微腔光梳在实际应用方面取得的进展,最后对微腔光梳当前的问题进行总结,并对未来发展进行展望.