Optical forces on arbitrary shaped particles in optical tweezers

2010 ◽  
Vol 108 (7) ◽  
pp. 073110 ◽  
Author(s):  
Lin Ling ◽  
Fei Zhou ◽  
Lu Huang ◽  
Zhi-Yuan Li
Keyword(s):  
Optical Tweezers ◽  
Optical Forces

scholarly journals Micromanipulation of mitotic chromosomes in PTK2 cells using laser-induced optical forces (“optical tweezers”)

1991 ◽  
Vol 197 (1) ◽  
pp. 21-35 ◽  
Author(s):  
Hong Liang ◽  
William H. Wright ◽  
Wei He ◽  
Michael W. Berns
Keyword(s):  
Optical Tweezers ◽  
Optical Forces ◽  
Mitotic Chromosomes

scholarly journals Feedback traps for virtual potentials

2017 ◽  
Vol 375 (2088) ◽  
pp. 20160217 ◽  
Author(s):  
Momčilo Gavrilov ◽  
John Bechhoefer
Keyword(s):  
Optical Tweezers ◽  
Single Molecule ◽  
Feedback Loop ◽  
Target Object ◽  
Optical Forces ◽  
First Law Of Thermodynamics ◽  
Average Work ◽  
Arbitrary Potential ◽  
Information Erasure ◽  
Long Protocol

Feedback traps are tools for trapping and manipulating single charged objects, such as molecules in solution. An alternative to optical tweezers and other single-molecule techniques, they use feedback to counteract the Brownian motion of a molecule of interest. The trap first acquires information about a molecule's position and then applies an electric feedback force to move the molecule. Since electric forces are stronger than optical forces at small scales, feedback traps are the best way to trap single molecules without ‘touching’ them (e.g. by putting them in a small box or attaching them to a tether). Feedback traps can do more than trap molecules: they can also subject a target object to forces that are calculated to be the gradient of a desired potential functionU(x). If the feedback loop is fast enough, it creates avirtual potentialwhose dynamics will be very close to those of a particle in an actual potentialU(x). But because the dynamics are entirely a result of the feedback loop—absent the feedback, there is only an object diffusing in a fluid—we are free to specify and then manipulate in time an arbitrary potentialU(x,t). Here, we review recent applications of feedback traps to studies on the fundamental connections between information and thermodynamics, a topic where feedback plays an even more fundamental role. We discuss how recursive maximum-likelihood techniques allow continuous calibration, to compensate for drifts in experiments that last for days. We consider ways to estimate work and heat, using them to measure fluctuating energies to a precision of ±0.03kTover these long experiments. Finally, we compare work and heat measurements of the costs of information erasure, theLandauer limitofkTln 2 per bit of information erased. We argue that, when you want to know the average heat transferred to a bath in a long protocol, you should measure instead the average work and then infer the heat using the first law of thermodynamics.This article is part of the themed issue ‘Horizons of cybernetical physics’.

Using GPUs for Realtime Prediction of Optical Forces on Microsphere Ensembles

2012 ◽  
Author(s):  
Sujal Bista ◽  
Sagar Chowdhury ◽  
Satyandra K. Gupta ◽  
Amitabh Varshney
Keyword(s):  
Laser Beam ◽  
Optical Tweezers ◽  
Computational Models ◽  
Laser Beams ◽  
Cell Manipulation ◽  
Optical Traps ◽  
Optical Forces ◽  
Gaussian Laser Beam ◽  
Multiple Particles ◽  
Speed Up

Laser beams can be used to create optical traps that can hold and transport small particles. Optical trapping has been used in a number of applications ranging from prototyping at the microscale to biological cell manipulation. Successfully using optical tweezers requires predicting optical forces on the particle being trapped and transported. Reasonably accurate theory and computational models exist for predicting optical forces on a single particle in the close vicinity of a Gaussian laser beam. However, in practice the workspace includes multiple particles that are manipulated using individual optical traps. It has been experimentally shown that the presence of a particle can cast a shadow on a nearby particle and hence affect the optical forces acting on it. Computing optical forces in the presence of shadows in real-time is not feasible on CPUs. In this paper, we introduce a ray-tracing-based application optimized for GPUs to calculate forces exerted by the laser beams on microparticle ensembles in an optical tweezers system. When evaluating the force exerted by a laser beam on 32 interacting particles, our GPU-based application is able to get a 66-fold speed up compared to a single core CPU implementation of traditional Ashkin’s approach and a 10-fold speedup over its single core CPU-based counterpart.

Nanowire-type plasmonic waveguides as strong and tunable optical tweezers

2019 ◽  
Vol 33 (07) ◽  
pp. 1950081 ◽  
Author(s):  
Shu Yang ◽  
Kang Zhao
Keyword(s):  
Long Range ◽  
Optical Tweezers ◽  
Optical Trapping ◽  
Near Field ◽  
Optical Forces ◽  
Plasmonic Waveguides ◽  
Trapping Forces

A series of nanowire-type plasmonic waveguides are proposed. The mode properties of these waveguides and their dependences on various geometry parameters are studied. It is shown that they can generate deep subwavelength confinement and long-range propagation simultaneously. Moreover, the optical forces exerted on dielectric nanoparticles by these waveguides are calculated. It is found that the optical trapping forces are very strong, and that their distribution can be effectively regulated by certain geometry parameters. Using these features, strong and tunable near-field optical tweezers can be designed.

scholarly journals Optomechanical measurement of photon spin angular momentum and optical torque in integrated photonic devices

2016 ◽  
Vol 2 (9) ◽  
pp. e1600485 ◽  
Author(s):  
Li He ◽  
Huan Li ◽  
Mo Li
Keyword(s):  
Angular Momentum ◽  
Optical Tweezers ◽  
Laser Cooling ◽  
Photonic Devices ◽  
Mechanical Effect ◽  
Linear Momentum ◽  
Polarization Degree ◽  
Optical Forces ◽  
Spin Angular Momentum ◽  
Optical Torque

Photons carry linear momentum and spin angular momentum when circularly or elliptically polarized. During light-matter interaction, transfer of linear momentum leads to optical forces, whereas transfer of angular momentum induces optical torque. Optical forces including radiation pressure and gradient forces have long been used in optical tweezers and laser cooling. In nanophotonic devices, optical forces can be significantly enhanced, leading to unprecedented optomechanical effects in both classical and quantum regimes. In contrast, to date, the angular momentum of light and the optical torque effect have only been used in optical tweezers but remain unexplored in integrated photonics. We demonstrate the measurement of the spin angular momentum of photons propagating in a birefringent waveguide and the use of optical torque to actuate rotational motion of an optomechanical device. We show that the sign and magnitude of the optical torque are determined by the photon polarization states that are synthesized on the chip. Our study reveals the mechanical effect of photon’s polarization degree of freedom and demonstrates its control in integrated photonic devices. Exploiting optical torque and optomechanical interaction with photon angular momentum can lead to torsional cavity optomechanics and optomechanical photon spin-orbit coupling, as well as applications such as optomechanical gyroscopes and torsional magnetometry.

scholarly journals Velocity-dependent optical forces and Maxwell’s demon

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
J. D. Franson
Keyword(s):  
Quantum Information ◽  
Laser Beam ◽  
Optical Tweezers ◽  
Optical Forces ◽  
Velocity Dependence ◽  
Photon Scattering ◽  
Maxwell’S Demon ◽  
Maxwell's Demon ◽  
Dipole Force ◽  
The Doppler Effect

Abstract An atom placed in a focused laser beam will experience a dipole force due to the gradient in the interaction energy, which is analogous to the well-known optical tweezers effect. This force will be dependent on the velocity of the atom due to the Doppler effect, which could potentially be used to implement a Maxwell’s demon. Photon scattering and other forms of dissipation can be negligibly small, which would seem to contradict quantum information proofs that a Maxwell’s demon must dissipate a minimum amount of energy. We show that the velocity dependence of the dipole force is cancelled out by another force that is related to the gradient in the phase of the laser beam. As a result, a Maxwell’s demon cannot be implemented in this way.

Optical Trapping, Sensing, and Imaging by Photonic Nanojets

Photonics ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 434
Author(s):  
Heng Li ◽  
Wanying Song ◽  
Yanan Zhao ◽  
Qin Cao ◽  
Ahao Wen
Keyword(s):  
Optical Tweezers ◽  
Optical Trapping ◽  
Near Field ◽  
Super Resolution ◽  
Diffraction Limit ◽  
Research Progress ◽  
Optical Forces ◽  
Resolution Imaging ◽  
Photonic Nanojets ◽  
Near Field Scanning

The optical trapping, sensing, and imaging of nanostructures and biological samples are research hotspots in the fields of biomedicine and nanophotonics. However, because of the diffraction limit of light, traditional optical tweezers and microscopy are difficult to use to trap and observe objects smaller than 200 nm. Near-field scanning probes, metamaterial superlenses, and photonic crystals have been designed to overcome the diffraction limit, and thus are used for nanoscale optical trapping, sensing, and imaging. Additionally, photonic nanojets that are simply generated by dielectric microspheres can break the diffraction limit and enhance optical forces, detection signals, and imaging resolution. In this review, we summarize the current types of microsphere lenses, as well as their principles and applications in nano-optical trapping, signal enhancement, and super-resolution imaging, with particular attention paid to research progress in photonic nanojets for the trapping, sensing, and imaging of biological cells and tissues.

Fluctuation of Position and Energy of a Fine Particle in Plasma Nanofabrication

2016 ◽  
Vol 879 ◽  
pp. 1772-1777 ◽  
Author(s):  
Masaharu Shiratani ◽  
Masahiro Soejima ◽  
Hyun Woong Seo ◽  
Naho Itagaki ◽  
Kazunori Koga
Keyword(s):  
Optical Tweezers ◽  
Fine Particle ◽  
Fine Particles ◽  
Electrostatic Force ◽  
Repulsive Force ◽  
Attractive Force ◽  
Coulomb Collision ◽  
Optical Forces ◽  
Ion Collisions ◽  
Guided Assembly

We are developing plasma nanofabrication, namely, nanoand micro scale guided assembly using plasmas. We manipulate nanoand micro objects using electrostatic, electromagnetic, ion drag, neutral drag, and optical forces. The accuracy of positioning the objects depends on fluctuation of position and energy of a fine particle (= each object) in plasmas. Here we evaluate such fluctuations and discuss the mechanism behind them. In the first experiment, we grabbed a fine particle in plasma using an optical tweezers. The fine particle moves in a potential well made by the optical tweezers. This is a kind of Brownian motion and the position fluctuation can be caused by neutral molecule collisions, ion collisions, and fluctuation of electrostatic force. Among theses possible causes, fluctuation of electrostatic force may be main one. In the second experiment, we deduced interaction potential between two fine particles during their Coulomb collision. We found that there exist repulsive and attractive forces between them. The repulsive force is a screened Coulomb one, whereas the attractive force is likely a force due to a shadow effect, a non-collective attractive force. Moreover, we noted that there is a fluctuation of the potential, probably due to fluctuation of electrostatic force. These position and potential energy fluctuations may limit the accuracy of guided assembly using plasmas.

Sign in / Sign up

Export Citation Format

Share Document