Optical trapping force with annular and doughnut laser beams based on vectorial diffraction

Ganic, Djenan; Gan, Xiaosong; Gu, Miṅ

doi:10.1364/opex.13.001260

Cited by 27 publications

(17 citation statements)

References 14 publications

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“…The difference of the trapping efficiency between the two types of beads becomes smaller as the size of the particles increase. The trapping efficiency for dielectric beads of diameter 25 mm approaches the value predicated by the ray optics model, 18 while the trapping efficiency for fluorescent beads of the same size is slightly decreased because the focal spot of the laser beam is much smaller than the bead, and only a small fraction of the bead volume is excited. The trapping efficiency of fluorescent beads of diameter 10 mm is approximately five times higher than the trapping efficiency of dielectric beads of the same size because the two-photon absorption under the low NA objective occurs within an interaction cross-section of the microbeads larger than the scattering cross-section, due to the greater surface-to-volume ratio.…”

Section: Resultsmentioning

confidence: 56%

“…In the case of dielectric beads, the trapping efficiency under the low NA illumination condition decreases when their size is reduced, which is consistent with the previous observation for high NA objective trapping. 18 Because the NA of nonlinear optical endoscopy is low, the trapping efficiency of dielectric beads is approximately 4.2310 26 for nanobeads of diameter 100 nm, and no trapping can be achieved when the trapping power is less than 35 mW. The difference of the trapping efficiency between the two types of beads becomes smaller as the size of the particles increase.…”

Section: Resultsmentioning

confidence: 99%

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Tweezing and manipulating micro- and nanoparticles by optical nonlinear endoscopy

Bao

Gan

et al. 2014

Light Sci Appl

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The precise control and manipulation of micro-and nanoparticles using an optical endoscope are potentially important in biomedical studies, bedside diagnosis and treatment in an aquatic internal organ environment, but they have not yet been achieved. Here, for the first time, we demonstrate optical nonlinear endoscopic tweezers (ONETs) for directly controlling and manipulating aquatic micro-and nanobeads as well as gold nanorods. It is found that two-photon absorption can enhance the trapping force on fluorescent nanobeads by up to four orders of magnitude compared with dielectric nanobeads of the same size. More importantly, two-photon excitation leads to a plasmon-mediated optothermal attracting force on nanorods, which can extend far beyond the focal spot. This new phenomenon facilitates a snowball effect that allows the fast uploading of nanorods to a targeted cell followed by thermal treatment within 1 min. As two-photon absorption allows an operation wavelength at the center of the transmission window of human tissue, our work demonstrates that ONET is potentially an unprecedented tool for precisely specifying the location and dosage of drug particles and for rapidly uploading metallic nanoparticles to individual cancer cells for treatment.

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Section: Resultsmentioning

confidence: 56%

Section: Resultsmentioning

confidence: 99%

Tweezing and manipulating micro- and nanoparticles by optical nonlinear endoscopy

Bao

Gan

et al. 2014

Light Sci Appl

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“…Double-beam subdiffraction lithography using two beams and direct laser writing also use a doughnutlike spot [2,3]. Another fascinating application is optical trapping, where the central dark zone of the doughnut spot is used to trap and manipulate tiny objects that are repelled and pushed away from the regions of maximum intensity [4,5].…”

Section: Introductionmentioning

confidence: 99%

Near-field self-induced hollow spot through localized heating of polycarbonate/ZnS stack layer

et al. 2012

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We have found an alternative way of achieving a doughnutlike focused spot by simply melting a subwavelength scatterer in a polycarbonate/ZnS sample. The near-field microscopy technique is used to directly measure the induced doughnut spot in the near-field regime. A numerical model based on rigorous solution of the Maxwell's equations is proposed to study the phenomena. The simulations help to understand the optical mechanism behind the spot formation.

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“…with doughnut beams have been investigated [34][35][36][37][38][39] in liquids. Here, we focus on the problem in vacuum which has low friction and low dissipation.…”

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confidence: 99%

Optical levitation of nanodiamonds by doughnut beams in vacuum

Zhou

Xiao

Chen

et al. 2017

Laser & Photonics Reviews

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Optically levitated nanodiamonds with nitrogen-vacancy centers promise a high-quality hybrid spinoptomechanical system. However, the trapped nanodiamond absorbs energy form laser beams and causes thermal damage in vacuum. It is proposed here to solve the problem by trapping a composite particle (a nanodiamond core coated with a less absorptive silica shell) at the center of strongly focused doughnut-shaped laser beams. Systematical study on the trapping stability, heat absorption, and oscillation frequency concludes that the azimuthally polarized Gaussian beam and the linearly polarized Laguerre-Gaussian beam LG 03 are the optimal choices. With our proposal, particles with strong absorption coefficients can be trapped without obvious heating and, thus, the spin-optomechanical system based on levitated nanodiamonds are made possible in high vacuum with the present experimental techniques.Introduction-. By trapping, detecting and manipulating nano-and micro-particles [1], optical tweezers are widely used in biophysics [2-4], colloidal sciences [5], chemistry, microfluidic dynamics [6], and fundamental physics [7][8][9][10][11][12][13][14][15]. Because of the wide applicability and high tunablity of the optically levitated systems, several schemes [16] were proposed to realize the ground-state cooling [17], to search for non-Newtonian gravity [18] and to detect gravitational wave [19]. Particularly, it brings about more interesting phenomena and novel applications [20,21] when the trapped particles have internal degrees of freedom (such as spins or electric dipoles) and enter the quantum regime.Optically levitated nanodiamonds with nitrogen-vacancy (NV) centers [22][23][24][25][26] are one of the most promising candidates for implementing a spin-optomechanical hybrid system. In principle, this system can have both long spin coherence time and high quality factor of mechanical oscillation in vacuum. The electron spins of NV centers were shown to have long spin coherence time (in the order of 10 2 µs) even in nanodiamonds of diameter about 20 nm [27]. When trapped in high-vacuum, the dielectric particles are predicted to have ultra-high quality factor Q larger than 10 10 [16,18,28]. Researchers have trapped diamond particles and observed the signal from NV centers in liquid [29,30], in air [31] and very recently in vacuum with pressure down to ∼ kPa [24,25] and ∼ 100 Pa [26].Realizing high quality mechanical oscillation requires trapping the particles in high vacuum (e.g, 10 −6 Pa) to get Q ∼ 10 10 . However, the high-vacuum condition usually causes the thermal damage problem, and experimentally trapping a nanodiamond in high vacuum is still very challenging. Nanodiamonds will absorb energy from the trapping laser beams due to the intrinsic defects [26] and the inevitable imperfections or graphitization [32] on diamond surface. The absorbed energy can hardly be dissipated in a high-vacuum environment, and the nanodiamonds will be quickly heated up significantly [24][25][26], which is unfavorable to the defect centers...

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Optical trapping force with annular and doughnut laser beams based on vectorial diffraction

Cited by 27 publications

References 14 publications

Tweezing and manipulating micro- and nanoparticles by optical nonlinear endoscopy

Tweezing and manipulating micro- and nanoparticles by optical nonlinear endoscopy

Near-field self-induced hollow spot through localized heating of polycarbonate/ZnS stack layer

Optical levitation of nanodiamonds by doughnut beams in vacuum

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