A model of Gaussian laser beam self-trapping in optical tweezers for nonlinear particles

2021 ◽  
Vol 53 (8) ◽  
Author(s):  
Quy Ho Quang ◽  
Thanh Thai Doan ◽  
Kien Bui Xuan ◽  
Thang Nguyen Manh
Keyword(s):  
Laser Beam ◽  
Optical Tweezers ◽  
Gaussian Laser Beam ◽  
Self Trapping

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.

scholarly journals Laser Self-Trapping in Optical Tweezers for Nonlinear Particles

2021 ◽  
Author(s):  
Quy Quang Ho ◽  
Thanh Doan Thai ◽  
Kien Xuan Bui ◽  
Thang Manh Nguyen
Keyword(s):  
Laser Beam ◽  
Optical Tweezers ◽  
Kerr Effect ◽  
Mass Density ◽  
The Self ◽  
Kerr Medium ◽  
Gradient Force ◽  
Trapping Region ◽  
Self Trapping ◽  
Particle Solution

Abstract The optical tweezers are used to trap the particles embedded in a suitable fluid. The optical trap efficiency is significantly enhanced for nonlinear particleswhich response to the Kerr effect. The optical transverse gradient force makes these particles’ mass density in trapping region increasing, and the Kerr medium can be created. When the laser Gaussian beam propagates through it, the self-focusing, and consequentlyself-trappingcan appear. In this paper, a model describing the laser self-trapping in nonlinear particle solution of optical tweezers is proposed. The expressions for the Kerr effect, effective refractive index of nonlinear particle solution and the intensity distribution of reshaped Gaussian laser beam are derived, and the self-trapping of laser beam is numerically investigated. Finally, the guide properties of nonlinear particles-filled trapping region and guiding condition are analysed and discussed.

scholarly journals Self-focusing and self-phase modulation of an elliptic Gaussian laser beam in collisionless magnetoplasma

2006 ◽  
Vol 24 (3) ◽  
pp. 447-453 ◽  
Author(s):  
NARESHPAL SINGH SAINI ◽  
TARSEM SINGH GILL
Keyword(s):  
Laser Beam ◽  
Phase Modulation ◽  
Beam Width ◽  
Magnetized Plasma ◽  
Combined Effects ◽  
Gaussian Laser Beam ◽  
Self Phase Modulation ◽  
Self Focusing ◽  
Variation Approach ◽  
Self Trapping

The problem of nonlinear self-focusing of elliptic Gaussian laser beam in collisionless magnetized plasma is studied using variation approach. The dynamics of the combined effects of nonlinearity and spatial diffraction is presented. With a and b as the beam width parameters of the beam along x and y directions, respectively, the phenomenon of cross-focusing is observed where focusing of a results in defocusing of b and vice versa. Although no stationary self-trapping is observed, oscillatory self-trapping occurs far below the threshold. The regularized phase is always negative.

Using GPUs for Realtime Prediction of Optical Forces on Microsphere Ensembles

2013 ◽  
Vol 13 (3) ◽  
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 approach 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 the single core CPU-based implementation of our approach.

Self-focusing of cosh-Gaussian laser beam in collisional plasma: effect of nonlinear absorption

2021 ◽  
Author(s):  
Naveen Gupta ◽  
Sandeep Kumar ◽  
A Gnaneshwaran ◽  
Sanjeev Kumar ◽  
Suman Choudhry
Keyword(s):  
Laser Beam ◽  
Nonlinear Absorption ◽  
Collisional Plasma ◽  
Gaussian Laser Beam ◽  
Self Focusing ◽  
Plasma Effect

Propagation of circularly polarized quadruple Gaussian laser beam in magnetoplasma

Optik ◽  
2015 ◽  
Vol 126 (24) ◽  
pp. 5710-5714 ◽  
Author(s):  
Munish Aggarwal ◽  
Shivani Vij ◽  
Niti Kant
Keyword(s):  
Laser Beam ◽  
Gaussian Laser Beam ◽  
Circularly Polarized

ORIENTATING MANIPULATION OF CYLINDRICAL PARTICLES WITH OPTICAL TWEEZERS

2008 ◽  
Vol 17 (04) ◽  
pp. 387-394 ◽  
Author(s):  
XIUDONG SUN ◽  
XUECONG LI ◽  
JIANLONG ZHANG
Keyword(s):  
Escherichia Coli ◽  
Carbon Nanotubes ◽  
Laser Beam ◽  
Optical Tweezers ◽  
Optical Trap ◽  
Polarization Direction ◽  
Beam Shape ◽  
E Coli ◽  
Potential Applications ◽  
Cylindrical Particles

Orientating manipulations of cylindrical particles were performed by optical tweezers. Vertical and horizontal manipulations of Escherichia coli (E. coli) were carried out by changing the trapping depth and the focused laser beam shape. It was found that carbon nanotubes bundles (CNTBs) could be rotated in the linear polarized optical trap until it orientated its long axis along the linear polarization direction of the laser beam. However, E.coli could not be orientated in this way. Corresponding mechanisms were discussed based on the anisomeric electric characters of CNTBs. These orientation technologies of cylindrical objects with optical trap have potential applications in assembling nano-electric devices.

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