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In situ calibrating optical tweezers with sinusoidal-wave drag force method

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Chinese Physics B 2015年第11期24卷 626-632页

作者：李迪周金华呼新尧钟敏成龚雷王自强王浩威李银妹 Department of Optics and optical Engineering University of Science and Technology of China Hefei National Laboratory for Physical Sciences at the Microscale

We introduce a corrected sinusoidal-wave drag force method （SDFM） into optical tweezers to calibrate the trapping stiffness of the optical trap and conversion factor （CF） of photodetectors. First, the theoretical analysis and experimental result demonstrate that the correction of SDFM is necessary, especially the error of no correction is up to 11.25% for a bead of 5μm in diameter. Second, the simulation results demonstrate that the SDFM has a better performance in the calibration of optical tweezers than the triangular-wave drag force method （TDFM） and power spectrum density method （PSDM） at the same signal-to-noise ratio or trapping stiffness. Third, in experiments, the experimental standard deviations of calibration of trapping stiffness and CF with the SDFM are about less than 50% of TDFM and PSDM especially at low laser power. Finally, the experiments of stretching DNA verify that the in situ calibration with the SDFM improves the measurement stability and accuracy.

关键词： optical tweezers trapping stiffness calibration conversion factor drag force method

Displacement Calibration of optical tweezers With Gravitational Acceleration

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Photonic Sensors 2023年第4期13卷 62-72页

作者： Jianyu YANG Nan LI Xunmin ZHU Ming CHEN Mian WU Xingfan CHEN Cheng LIU Jian ZHUANG Huizhu HU College of optical Science and Engineering Zhejiang UniversityHangzhou 310027China Quantum Sensing Center Zhejiang LabHangzhou 310000China State Key Laboratory of Modern optical Instrumentation Zhejiang UniversityHangzhou 310027China HIWING Technology Academy of CASIC Beijing 100074China

In recent years,levitated particles of optical traps in vacuum have shown the enormous potential for precision sensor development and new physics ***,the accuracy of the sensor is still hampered by the uncertainty of the calibration factor relating the detected signal to the absolute displacement of the trapped *** this paper,we suggest and experimentally demonstrate a novel calibration method for optical tweezers based on free-falling particles in vacuum,where the gravitational acceleration is introduced as an absolute *** work provides a calibration protocol with a great certainty and traceability,which is significant in improving the accuracy of precision sensing based on levitated optomechanical systems.

关键词： optical tweezers calibration free-falling particles

A novel approach to study the interactions between polymeric stabilized micron-sized oil droplets by optical tweezers

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Chinese Journal of Chemical Engineering 2020年第5期28卷 1368-1374页

作者： An Chen Shaowei Li Jianhong Xu The State Key Lab of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China

The well understanding of interaction forces between single dispersed droplets is crucial to the understanding of emulsion stabilization ***,many studies have reported the direct quantitative measurements of interaction forces between 20-200μm single droplet coated polymers by atomic force microscope(AFM).These studies have revealed many important results about the relationship of the interaction forces and the droplet ***,these studies of the quantitative relationship between the measured interaction forces and the separation distance of the front end of the droplet have rarely been *** tweezer instrument can make it possible to establish the quantitative relationship between the measured force and the separation distance of the front end of the droplet,which will make better understanding of the interaction mechanisms between *** to the differences of the measuring mechanism between atomic force microscopy(AFM)and optical tweezers,the theory model of AFM measurements cannot be fitted with the force measurement by optical *** have made an exhaustive comparison of the measuring differences between AFM and optical tweezer instrument in this ***,we built a numerical model to derive the repulsive pressure through the measured force curve in order to quantify the measured force of two micron-sized oil droplet coated polymers by optical ***,the novel method can be extended to other micron-sized emulsion systems,and these findings will be a vital progress on quantitative force measurements between micron-sized droplets.

关键词： Emulsions Stabilization mechanism Interactions Polymers optical tweezers

Influence of viscous force on the dynamic process of micro-sphere in optical tweezers

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Chinese Physics B 2023年第10期32卷 768-775页

作者：刘静吴星宇冯怡敏郑冕李志远 College of Computer Science South-Central Minzu UniversityWuhan 430074China China Ship Development and Design Center Wuhan 430064China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

With the advantages of noncontact,high accuracy,and high flexibility,optical tweezers hold huge potential for micro-manipulation and force ***,the majority of previous research focused on the state of the motion of particles in the optical trap,but paid little attention to the early dynamic process between the initial state of the particles and the optical *** that the viscous forces can greatly affect the motion of *** this paper,based on the equations of Newtonian mechanics,we investigate the dynamics of laser-trapped micro-spheres in the surrounding environment with different viscosity *** the calculations,over time the particle trajectory clearly reveals the subtle details of the optical capture process,including acceleration,deceleration,turning,and reciprocating *** time to equilibrium mainly depends on the corresponding damping coefficient of the surrounding environment and the oscillation frequency of the optical *** studies are essential for understanding various mechanisms to engineer the mechanical motion behavior of molecules or microparticles in liquid or air.

关键词： optical tweezers viscous force equations of Newtonian mechanics Runge–Kutta method

Light-Induced Agglomeration and Diffusion of Different Particles with optical tweezers

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Chinese Physics Letters 2010年第9期27卷 221-224页

作者：李雪璁孙秀冬刘鸿鹏张建隆 Department of Physics Harbin Institute of Technology Harbin 150001

The dynamic process of light-induced agglomeration of carbon nanotubes （CNTs）, C60 and Escherichia coli （***） in aqueous solutions is demonstrated using an optical tweezers system. Based on the results, the diameter of the agglomerated region and the agglomeration rate increase with the increasing laser power. After the saturation-stable period, CNTs diffuse completely, C60 clusters only diffuse partially, and E. coli never diffuses in the agglomeration region. Theoretical analyses show that the molecular polarization and thermal diffusion of particles play crucial roles in the diffusion process. The and sort nanoparticles. results indicate the possibility of using light to aggregate

关键词： optical tweezers DIFFUSION CARBON nanotubes optical polarization ESCHERICHIA coli SALTWATER solutions AGGLOMERATION (Materials) NANOPARTICLES

Robust and high-speed rotation control in optical tweezers by using polarization synthesis based on heterodyne interference

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Opto-Electronic Advances 2020年第8期3卷 23-29页

作者： Wei Liu Dashan Dong Hong Yang Qihuang Gong Kebin Shi State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China Peking University Yangtze Delta Institute of Optoelectronics Nantong 226010China

The rotation control of particles in optical tweezers is often subject to the spin or orbit angular momentum induced optical torque,which is susceptible to the mechanical and morphological properties of individual *** we report on a robust and high-speed rotation control in optical tweezers by using a novel linear polarization synthesis based on optical heterodyne interference between two circularly polarized lights with opposite *** synthesized linear polarization can be rotated in a hopping-free scheme at arbitrary speed determined electronically by the heterodyne frequency between two laser *** experimental demonstration of a trapped vaterite particle in water shows that the precisely controlled rotation frequency of 300 Hz can be *** proposed method will find promising applications in optically driven micro-gears,fluidic pumps and rotational micro-rheology.

关键词： polarization modulation optical heterodyne optical tweezers optical rotation

Displacement and Force Measurements with Quadrant Photodetector in optical tweezers

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Chinese Physics Letters 2003年第6期20卷 950-952页

作者： GUOHong-Lian LIUChun-Xiang LIZhao-Lin DUANJian-Fa HANXue-Hai CHENGBing-Ying ZHANGDao-Zhong opticalPhysicsLaboratory InstituteofPhysicsandCenterforCondensedMatterPhysicsChineseAcademyofSciencesBeijing100080 StateKeyLaboratoryofBiomacromolecles InstituteofBiophysicsChineseAcademyofSciencesBeijing100101

A technique of displacement and force measurements with a photodiode quadrant detector in an optical tweezers system is presented. The stiffness of optical trap is calibrated and the leukemia cell membrane tension is measured. The results show that the optical tweezers combined with the quadrant detector is a very useful tool for detecting the displacement and force with a millisecond-order response.

关键词： optical tweezers

Simultaneous, hybrid single-molecule method by optical tweezers and fluorescence

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Nanotechnology and Precision Engineering 2019年第4期2卷 145-156页

作者： Guoteng Ma Chunguang Hu Shuai Li Xiaoqin Gao Hongbin Li Xiaotang Hu State Key Laboratory of Precision Measuring Technology and Instruments Tianjin University300072China Nanchang Institute for Microtechnology of Tianjin University Tianjin 300072China Department of Chemistry University of British ColumbiaVancouverBC V6T 1Z1Canada

As studies on life sciences progress toward the single-molecule level,new experiments have put forward more requirements for simultaneously displaying the mechanical properties and conformational changes of *** tweezers and fluorescence microscopy have been combined to solve this *** combination of instruments forms a new generation of hybrid single-molecule technology that breaks through the limitations of traditional biochemical *** and fluorescence visualization have beenwidely used,and these techniques provide new possibilities for studying complex biochemical reactions at the singlemolecule *** paper explains the features of this combined technique,including the application characteristics of single-trap and dual-traps,the anti-bleaching method,and optical tweezers combined with epifluorescence,confocal fluorescence,total internal reflection fluorescence,and other fluorescence *** typical experiments,we analyze technical solutions and explain the factors and principles that instrument designers should *** review aims to give an introduction to this novel fusion technology process and describe important biological results.

关键词： Single-molecule optical tweezers Confocal fluorescence FRET TIRF

3D dynamic motion of a dielectric micro-sphere within optical tweezers

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Opto-Electronic Advances 2021年第1期4卷 14-24页

作者： Jing Liu Mian Zheng Zhengjun Xiong Zhiyuan Li Institute of Laser and Intelligent Manufacturing Technology South-Central University for NationalitiesWuhan 430074China China Ship Development and Design Center Wuhan 430064China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China

Known as laser trapping,optical tweezers,with nanometer accuracy and pico-newton precision,plays a pivotal role in single bio-molecule measurements and controllable motions of *** order to advance the flourishing applications for those achievements,it is necessary to make clear the three-dimensional dynamic process of micro-particles stepping into an optical *** this paper,we utilize the ray optics method to calculate the optical force and optical torque of a micro-sphere in optical *** the influence of viscosity force and torque taken into account,we numerically solve and analyze the dynamic process of a dielectric micro-sphere in optical tweezers on the basis of Newton mechanical equations under various conditions of initial positions and velocity vectors of the *** particle trajectory over time can demonstrate whether the particle can be successfully trapped into the optical tweezers center and reveal the subtle details of this trapping *** in a simple pair of optical tweezers,the dielectric micro-sphere exhibits abundant phases of mechanical motions including acceleration,deceleration,and *** studies will be of great help to understand the particle-laser trap interaction in various situations and promote exciting possibilities for exploring novel ways to control the mechanical dynamics of microscale particles.

关键词： optical tweezers 3D dynamic motion ray optics method Newton mechanical equations