Optical trapping of fluorescent beads

Bhatt, Jitendra; Kumar, Ashok; Singh, R. P.; Jaaffrey, S. N. A.

doi:10.1080/17458080.2013.828244

Cited by 3 publications

(3 citation statements)

References 20 publications

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“…In fact, the fluorescence intensity showed a quadratic dependence on the excitation power, resulting from a two-photon excitation under fast illumination. Bhatt et al [ 180 ] used optical forces to trap various polystyrene beads. They had trouble with trapping fluorescent particles, with quasi impossibility when the maximum excitation wavelength was too close to the trapping laser, 540 nm and 532 nm, respectively.…”

Section: Single-particle Laser-based Characterizationmentioning

confidence: 99%

Optical-Trapping Laser Techniques for Characterizing Airborne Aerosol Particles and Its Application in Chemical Aerosol Study

2021

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We present a broad assessment on the studies of optically-trapped single airborne aerosol particles, particularly chemical aerosol particles, using laser technologies. To date, extensive works have been conducted on ensembles of aerosols as well as on their analogous bulk samples, and a decent general description of airborne particles has been drawn and accepted. However, substantial discrepancies between observed and expected aerosols behavior have been reported. To fill this gap, single-particle investigation has proved to be a unique intersection leading to a clear representation of microproperties and size-dependent comportment affecting the overall aerosol behavior, under various environmental conditions. In order to achieve this objective, optical-trapping technologies allow holding and manipulating a single aerosol particle, while offering significant advantages such as contactless handling, free from sample collection and preparation, prevention of contamination, versatility to any type of aerosol, and flexibility to accommodation of various analytical systems. We review spectroscopic methods that are based on the light-particle interaction, including elastic light scattering, light absorption (cavity ring-down and photoacoustic spectroscopies), inelastic light scattering and emission (Raman, laser-induced breakdown, and laser-induced fluorescence spectroscopies), and digital holography. Laser technologies offer several benefits such as high speed, high selectivity, high accuracy, and the ability to perform in real-time, in situ. This review, in particular, discusses each method, highlights the advantages and limitations, early breakthroughs, and recent progresses that have contributed to a better understanding of single particles and particle ensembles in general.

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Section: Single-particle Laser-based Characterizationmentioning

confidence: 99%

Optical-Trapping Laser Techniques for Characterizing Airborne Aerosol Particles and Its Application in Chemical Aerosol Study

2021

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“…By this collective mechanism, the spatially localized forces induced on the objects by the laser beam may potentially activate nonlinear terms in the NPs flow . It is known that above a certain threshold in the volume fraction of the NPs (about ϕ = 10 –4 ) and driving energy (about 1 k B T /particle), hydrodynamic interactions between optically driven NPs can create interesting collective phenomena, such as swarming and superlinear scaling of the flow of NPs, with the laser power. ,, It has to be mentioned that only a few works in optical trapping describe the kinetics of particle incorporation into and escaping from trapping sites. , This is likely because the phenomenon occurs intrinsically in 3D, while standard setups are only able to acquire two-dimensional ( x – y ) data, which obtains a mere projection of the three-dimensional phenomenon.…”

Section: Introductionmentioning

confidence: 99%

“…21,22,32 It has to be mentioned that only a few works in optical trapping describe the kinetics of particle incorporation into and escaping from trapping sites. 37,38 This is likely because the phenomenon occurs intrinsically in 3D, while standard setups are only able to acquire two-dimensional (x− y) data, which obtains a mere projection of the threedimensional phenomenon.…”

Section: Introductionmentioning

confidence: 99%

Unravelling 3D Dynamics and Hydrodynamics during Incorporation of Dielectric Particles to an Optical Trapping Site

et al. 2023

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Mapping of the spatial and temporal motion of particles inside an optical field is critical for understanding and further improvement of the 3D spatio-temporal control over their optical trapping dynamics. However, it is not trivial to capture the 3D motion, and most imaging systems only capture a 2D projection of the 3D motion, in which the information about the axial movement is not directly available. In this work, we resolve the 3D incorporation trajectories of 200 nm fluorescent polystyrene particles in an optical trapping site under different optical experimental conditions using a recently developed widefield multiplane microscope (imaging volume of 50 × 50 × 4 μm3). The particles are gathered at the focus following some preferential 3D channels that show a shallow cone distribution. We demonstrate that the radial and the axial flow speed components depend on the axial distance from the focus, which is directly related to the scattering/gradient optical forces. While particle velocities and trajectories are mainly determined by the trapping laser profile, they cannot be completely explained without considering collective effects resulting from hydrodynamic forces.

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Optical trapping of microparticles with two tilted-focused laser beams

Meng

Zhang

et al. 2023

Review of Scientific Instruments

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We present an optical method for the manipulation of microparticles using two tilted-focused beams. First, the action on the microparticles is studied with a single tilted-focused beam. The beam is used to drive the directional motion of a dielectric particle. When the optical scattering force is larger than the optical gradient force, the particle is pushed to the tilted side of the optical axis by the optical force. Second, two tilted-focused beams with the same power and complementary tilt angles are used to assemble an optical trap. The trap can be used to realize the optical trapping of the dielectric particles and opto-thermal trapping of the light absorbing particles. The trapping mechanism is the balance of the forces exerted on the particles, including the optical scattering force, optical gradient force, gravity, and thermal gradient force. The trap center is away from the focal spots, which effectively prevents the laser beam from being focused on the trapped object.

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Optical trapping of fluorescent beads

Cited by 3 publications

References 20 publications

Optical-Trapping Laser Techniques for Characterizing Airborne Aerosol Particles and Its Application in Chemical Aerosol Study

Optical-Trapping Laser Techniques for Characterizing Airborne Aerosol Particles and Its Application in Chemical Aerosol Study

Unravelling 3D Dynamics and Hydrodynamics during Incorporation of Dielectric Particles to an Optical Trapping Site

Optical trapping of microparticles with two tilted-focused laser beams

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