Modeling and experimental exploration of the underdamped motion of microbeads in optical tweezers

Bowling, Alan; Joshi, Vatsal; Haghshenas-Jaryani, Mahdi

doi:10.1117/12.2530017

Cited by 3 publications

(2 citation statements)

References 22 publications

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“…A previous study 2 showed that a nanoparticle can exhibit underdamped motion, i.e., move past the focal point and return to it. Many possible reasons [3][4][5][6][7] were identified that may explain this phenomenon, which can be classified into two broad categories corresponding to fluid or laser forces acting on the particle. The focus herein is to isolate the effects of each major force and analyze them in detail.…”

Section: Introductionmentioning

confidence: 99%

Exploring nanodynamics with optical and dielectrophoretic trapping

Joshi,

Danesh,

Moon

et al. 2023

Optical Trapping and Optical Micromanipulation XX

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It has been observed that a nanoparticle can exhibit underdamped motion while moving toward the focal point of an optical trap. It is unclear whether this motion is caused by laser or fluid forces. Dielectrophoretic forces can trap nanoparticles as an alternate approach to optical trapping. The electrical trap uses no laser, so we can determine which force causes the underdamped motion. A microchannel with a quad-electrode arrangement on its ceiling and floor was designed to explore this question. Supplying an oscillating voltage to these electrodes generates an oscillating electric field resulting in the dielectrophoretic force that traps the particle. However, matching common characteristics, such as trap stiffness, is difficult between the two methods. This paper compares the two approaches for a 2 µm diameter particle. Instead of matching the trapping characteristics, the next step in this work is to use the dielectrophoretic device to explore the effect of the particle's momentum on its motion, which can explain the underdamped motion. Combining optical and dielectrophoretic trapping will offer new insights into the dynamic behavior of small particles in a fluid medium.

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Section: Introductionmentioning

confidence: 99%

Exploring nanodynamics with optical and dielectrophoretic trapping

Joshi,

Danesh,

Moon

et al. 2023

Optical Trapping and Optical Micromanipulation XX

Self Cite

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“…5 However, it has been shown that it is important to model the inertia force because it can affect a small body's motion. [6][7][8] The large disproportion between the magnitudes of the inertia and viscous drag forces yields a stiff system. Such systems require large computation times to solve if explicit solvers such as Runge-Kutta methods are used.…”

Section: Introductionmentioning

confidence: 99%

Power spectral density analysis of a scaled model simulation of an optical tweezer

2022

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The majority of microscale and nanoscale mechanical systems encountered in the world are stiff. One example of such a system is a microbead trapped in an optical tweezer. For this example, the ratio of a body's mass to the viscous damping coefficient is negligible. Apart from being stiff, this system is also stochastic meaning that the differential equations representing the system include a random variable. This type of model can be solved with existing stochastic differential equation (SDE) solvers. Addressing the stochastic nature of the model usually requires averaging the results of multiple simulations. The computational time required to run the hundreds of simulations that may be necessary to obtain a useful average can be prohibitive. This paper presents a scaling approach that significantly reduces the computational time required to obtain these averages. However, this scaling changes the model and therefore the power spectral density (PSD) of the predicted motion. This work provides a general analysis of a mass-spring-damper model, such as an optical tweezer, that clearly shows the effect of scaling on the frequency content of the stochastic system. This analysis shows that the scaling technique can be used effectively without much loss of information. An experimental dataset of a 2 μm diameter microbead falling into an optical trap is compared with the simulation for validating the scaling method.

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Investigation of the power spectral density of a scaled model simulation of an optical tweezer

Joshi

Bowling

2022

Optical Trapping and Optical Micromanipulation XIX

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Modeling and experimental exploration of the underdamped motion of microbeads in optical tweezers

Cited by 3 publications

References 22 publications

Exploring nanodynamics with optical and dielectrophoretic trapping

Exploring nanodynamics with optical and dielectrophoretic trapping

Power spectral density analysis of a scaled model simulation of an optical tweezer

Investigation of the power spectral density of a scaled model simulation of an optical tweezer

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