scholarly journals Steady state of overdamped particles in the non-conservative force field of a simple non-linear model of optical trap

2021 ◽  
Vol 2021 (11) ◽  
pp. 113205
Author(s):  
Matthieu Mangeat ◽  
Thomas Guérin ◽  
David S Dean
Keyword(s):  
Steady State ◽  
Force Field ◽  
Brownian Particle ◽  
Optical Trap ◽  
Three Dimensional ◽  
Planck Equation ◽  
Steady State Probability ◽  
Trapped Particles ◽  
Scattering Force ◽  
Optically Trapped

Abstract Optically trapped particles are often subject to a non-conservative scattering force arising from radiation pressure. In this paper, we present an exact solution for the steady state statistics of an overdamped Brownian particle subjected to a commonly used force field model for an optical trap. The model is the simplest of its kind that takes into account non-conservative forces. In particular, we present the exact results for certain marginals of the full three-dimensional steady state probability distribution, in addition to results for the toroidal probability currents that are present in the steady state, as well as for the circulation of these currents. Our analytical results are confirmed by numerical solution of the steady state Fokker–Planck equation.

EFFECTS OF CORRELATED NOISES IN A SATURATION LASER MODEL

2006 ◽  
Vol 20 (23) ◽  
pp. 1481-1488 ◽  
Author(s):  
P. ZHU ◽  
S. B. CHEN ◽  
D. C. MEI
Keyword(s):  
Steady State ◽  
Intensity Fluctuation ◽  
Laser System ◽  
Planck Equation ◽  
Steady State Probability ◽  
Multiplicative Noises ◽  
Analytic Expressions ◽  
Laser Model ◽  
Correlation Strength ◽  
Correlated Noises

The effects of correlations between additive and multiplicative noises in a saturation laser model are investigated. The approximative Fokker–Planck equation and analytic expressions of the steady-state probability distribution function (SPD) of the laser system are derived. Based on the SPD, the normalized mean, the normalized variance, and the normalized skewness of the steady-state laser intensity are calculated numerically. Our results indicate that: (i) For the laser being operated above threshold, the correlation strength λ reduces the intensity fluctuation; (ii) For the laser being operated near threshold and below threshold, the correlation strength λ enhances the intensity fluctuation.

scholarly journals High-Performance Image-Based Measurements of Biological Forces and Interactions in a Dual Optical Trap

2018 ◽  
Author(s):  
Jessica L. Killian ◽  
James T. Inman ◽  
Michelle D. Wang
Keyword(s):  
High Performance ◽  
Optical Trap ◽  
Optical Traps ◽  
Trapped Particles ◽  
Accuracy And Precision ◽  
Potential Alternative ◽  
Molecular Forces ◽  
Sense And Respond ◽  
Direct Encounter ◽  
Optically Trapped

AbstractOptical traps enable nanoscale manipulation of individual biomolecules while measuring molecular forces and lengths. This ability relies on the sensitive detection of optically trapped particles, typically accomplished using laser-based interferometric methods. Recently, precise and fast image-based particle tracking techniques have garnered increased interest as a potential alternative to laser-based detection, however successful integration of image-based methods into optical trapping instruments for biophysical applications and force measurements has remained elusive. Here we develop a camera-based detection platform that enables exceptionally accurate and precise measurements of biological forces and interactions in a dual optical trap. In demonstration, we stretch and unzip DNA molecules while measuring the relative distances of trapped particles from their trapping centers with sub-nanometer accuracy and precision, a performance level previously only achieved using photodiodes. We then use the DNA unzipping technique to localize bound proteins with extraordinary sub-base-pair precision, revealing how thermal DNA fluctuations allow an unzipping fork to sense and respond to a bound protein prior to a direct encounter. This work significantly advances the capabilities of image tracking in optical traps, providing a state-of-the-art detection method that is accessible, highly flexible, and broadly compatible with diverse experimental substrates and other nanometric techniques.

scholarly journals Tunable optical lattices in the near-field of a few-mode nanophotonic waveguide

2019 ◽  
Vol 215 ◽  
pp. 14001
Author(s):  
Christophe Pin ◽  
Jean-Baptiste Jager ◽  
Manon Tardif ◽  
Emmanuel Picard ◽  
Emmanuel Hadji ◽  
...  
Keyword(s):  
Light Propagation ◽  
Near Field ◽  
Laser Wavelength ◽  
Optical Traps ◽  
Trapped Particles ◽  
Periodic Arrays ◽  
Dielectric Particles ◽  
Light Coupling ◽  
Scattering Force ◽  
Optically Trapped

Due to the action of the scattering force, particles that are optically trapped at the surface of a waveguide are propelled in the direction of the light propagation. In this work, we demonstrate an original approach for creating tunable periodic arrays of optical traps along a few-mode silicon nanophotonic waveguide. We show how the near-field optical forces at the surface of the waveguide are periodically modulated when two guided modes with different propagation constants are simultaneously excited. The phenomenon is used to achieve stable trapping of a large number of dielectric particles or bacteria along a single waveguide. By controlling the light coupling conditions and the laser wavelength, we investigate several techniques for manipulating the trapped particles. Especially, we demonstrate that the period of the optical lattice can be finely tuned by adjusting the laser wavelength. This effect can be used to control the trap positions, and thus transport the trapped particles in both directions along the waveguide.

scholarly journals Multipreconditioned GMRES for simulating stochastic automata networks

2018 ◽  
Vol 16 (1) ◽  
pp. 986-998
Author(s):  
Chun Wen ◽  
Ting-Zhu Huang ◽  
Xian-Ming Gu ◽  
Zhao-Li Shen ◽  
Hong-Fan Zhang ◽  
...  
Keyword(s):  
Steady State ◽  
Probability Distribution ◽  
Linear Systems ◽  
Iterative Methods ◽  
Communication Systems ◽  
Queueing Systems ◽  
Steady State Probability ◽  
Stochastic Automata ◽  
Automata Networks ◽  
Generator Matrices

AbstractStochastic Automata Networks (SANs) have a large amount of applications in modelling queueing systems and communication systems. To find the steady state probability distribution of the SANs, it often needs to solve linear systems which involve their generator matrices. However, some classical iterative methods such as the Jacobi and the Gauss-Seidel are inefficient due to the huge size of the generator matrices. In this paper, the multipreconditioned GMRES (MPGMRES) is considered by using two or more preconditioners simultaneously. Meanwhile, a selective version of the MPGMRES is presented to overcome the rapid increase of the storage requirements and make it practical. Numerical results on two models of SANs are reported to illustrate the effectiveness of these proposed methods.

scholarly journals The first observation of 4D tomography measurement of plasma structures and fluctuations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chanho Moon ◽  
Kotaro Yamasaki ◽  
Yoshihiko Nagashima ◽  
Shigeru Inagaki ◽  
Takeshi Ido ◽  
...  
Keyword(s):  
Steady State ◽  
Three Dimensional ◽  
Axial Direction ◽  
Axial Position ◽  
Entire Cross Section ◽  
Helicon Plasma ◽  
Emission Profile ◽  
Dimensional Measurement ◽  
Tomography System ◽  
Three Dimensional Measurement

AbstractA tomography system is installed as one of the diagnostics of new age to examine the three-dimensional characteristics of structure and dynamics including fluctuations of a linear magnetized helicon plasma. The system is composed of three sets of tomography components located at different axial positions. Each tomography component can measure the two-dimensional emission profile over the entire cross-section of plasma at different axial positions in a sufficient temporal scale to detect the fluctuations. The four-dimensional measurement including time and space successfully obtains the following three results that have never been found without three-dimensional measurement: (1) in the production phase, the plasma front propagates from the antenna toward the end plate with an ion acoustic velocity. (2) In the steady state, the plasma emission profile is inhomogeneous, and decreases along the axial direction in the presence of the azimuthal asymmetry. Furthermore, (3) in the steady state, the fluctuations should originate from a particular axial position located downward from the helicon antenna.

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