Rigorous time domain simulation of momentum transfer between light and microscopic particles in optical trapping

Zhang, Dianwen; Yuan, X.-C.; Tjin, Swee Chuan; Sathiyamoorthy, Krishnan

doi:10.1364/opex.12.002220

Cited by 26 publications

(11 citation statements)

References 8 publications

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“…Figures 2(a)-(d) show the longitudinal views of the simulated E-field distributions with different diameter spheres trapped at a position of 20 nm from the fibre surface. The input power is also normalized to be 1 W. The optical force F exerted on the sphere by the evanescent wave field around the fibre is calculated using F = (n/c) SdA [28], where n is the refractive index of the surround medium (water), c is the speed of light in vacuum and S is the difference between the energy density flux through the unit area travelling into and coming out of the sphere. The force F consists of two components.…”

Section: Theoretical Analysismentioning

confidence: 99%

Size-dependent trapping and delivery of submicro-spheres using a submicrofibre

Xu¹,

Li²,

Li³

2012

New J. Phys.

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We report size-dependent trapping and delivery of polystyrene submicro-spheres using a 600 nm diameter fibre. Theoretical results show that both gradient and scattering forces exerted on polystyrene submicro-spheres by the evanescent wave field around the submicrofibre increase with an increase in the sphere diameter, and the delivery velocity of the bigger spheres is also higher than that of smaller spheres. To support the theoretical predictions, experiments were performed using polystyrene spheres with diameters of 230, 400, 530 and 700 nm by injecting a 532 nm green laser into the fibre. The results demonstrate that spheres with larger diameter can be more easily trapped to the surface of the fibre and delivered in the propagation direction of the laser at a low input laser power. Contents

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Section: Theoretical Analysismentioning

confidence: 99%

Size-dependent trapping and delivery of submicro-spheres using a submicrofibre

Xu¹,

Li²,

Li³

2012

New J. Phys.

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“…In these respects, the numerical simulations allow us to strictly test the validity of the theoretical analysis. Previously, other authors calculated by FDTD techniques the optical pressure on dielectric media [32][33][34][35][36][37] (see also [38] for other approaches); to the best of our knowledge nonlinearity has not been considered before.…”

Section: Nonlinear Maxwell Equationsmentioning

confidence: 99%

Nonlinear optomechanical pressure

Conti

Boyd

2014

Phys. Rev. A

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A transparent material exhibits ultra-fast optical nonlinearity and is subject to optical pressure if irradiated by a laser beam. However, the effect of nonlinearity on optical pressure is often overlooked, even if a nonlinear optical pressure may be potentially employed in many applications, as optical manipulation, biophysics, cavity optomechanics, quantum optics, optical tractors, and is relevant in fundamental problems as the Abraham-Minkoswky dilemma, or the Casimir effect. Here we show that an ultra-fast nonlinear polarization gives indeed a contribution to the optical pressure that also is negative in certain spectral ranges; the theoretical analysis is confirmed by first-principles simulations. An order of magnitude estimate shows that the effect can be observable by measuring the deflection of a membrane made by graphene.PACS numbers: 42.50.Wk The mechanical effect of light has been the subject of the investigations of many scientists for more than three centuries, as recently reviewed in [1]. Foundational works have driven the emergence of fields of research, as, for example, optical tweezing and laser cooling [2], quantum noise in interferometers [3], and cavity optomechanics [4]. Even if many aspects of opto-mechanical forces have been largely investigated, there are still several open problems, including, among others, the effect of the optical nonlinearity on the laser induced pressure. As shown in recent papers [5,6], opto-mechanical deformations may produce huge optical nonlinearities, but if the opposite also holds true is at the moment unknown.When considering a possible effect of an intensity dependent refractive index on the optical pressure, it is important to consider the issue of the form of the momentum of a photon in a dielectric. Indeed the related debate has characterized the literature on optomechanical effects [7,8]. The Abraham or the Minkoswky expressions of the photon momentum are to be chosen depending on the distinction between the canonical (i.e., the generator of translations) and the kinetic momentum [9]. Even if in the absence of resonant light-matter interaction, it is accepted that the Abraham form is the correct one, one may question what is the role of the always-present ultrafast optical nonlinearity of electronic origin and, specifically, of an intensity-dependent refractive index. The very same use of the Maxwell stress tensor, and the expression of the Abraham force may also be questioned in the presence of nonlinearity. This is an important issue in several fields, including, among others, optical manipulation [10][11][12][13][14][15], cavity optomechanics [1,16], biophysics [17][18][19][20], quantum optics [21][22][23], optomechanics [5,6].The Balazs block (BB) furnishes a simple way for understanding the origin of the optical pressure [24]: a cubic piece of transparent matter obeying the Newton law in the absence of friction is irradiated by an electromagnetic (EM) wave (see Fig.1). As a photon travels through the block, it is slowed down , and the block is dis...

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“…On contrary, if λ << d , the particle can be treated as a point dipole, and the scattering and gradient force can be separated. Recently, with the developping of FDTD, in 2004 Dianwen Zhang and in 2005 Robert C. Ganthier simulated the trapping force in Gaussian beam using FDTD algorithm, respectively [10,11]. Ref [12] comment on this two papers and pointed that "two step" method using in Ref [10,11] is inappropriate for the principle of the momentum conservation.…”

Section: Introductionmentioning

confidence: 99%

A New Method Based on Conservation Momentum to Calculate the Trapping Force Using FDTD Algorithm

Yang

Feng

Zhou

et al. 2010

2010 Symposium on Photonics and Optoelectronics

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In this paper, A new method based on the conservation of momentum theory to calculate the trappping force on microsphere are presented. Using 2-D FDTD algorithm, the distribution of electric and magnetic fields in trapping system is simulated, then the monmentum density distribution and trapping force can be easily getted. Many parameters are taken into accounted involving wavelength of optical source, waist radius, diameter of microsphere and refractive index. The simulation results are in good aggreement with the other experimental observation.

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Rigorous time domain simulation of momentum transfer between light and microscopic particles in optical trapping

Cited by 26 publications

References 8 publications

Size-dependent trapping and delivery of submicro-spheres using a submicrofibre

Size-dependent trapping and delivery of submicro-spheres using a submicrofibre

Nonlinear optomechanical pressure

A New Method Based on Conservation Momentum to Calculate the Trapping Force Using FDTD Algorithm

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