Dark-field optical tweezers for nanometrology of metallic nanoparticles

Pearce, Kellie; Wang, Fan; Reece, Peter J.

doi:10.1364/oe.19.025559

Cited by 28 publications

(20 citation statements)

References 23 publications

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“…A direct result off the more discrete nature of the trapped Rayleigh particles is that we do not observe a Lorentzian lineshape in the position fluctuation analysis, and a Gaussian particle displacement histogram cannot be obtained. Thus, we rely on dark field video microscopy of the particles to verify that they are indeed trapped926. Despite these apparent complications, fs nanotweezers can greatly benefit biological applications not only because they function at power levels approximately 3 orders of magnitude lower than the optical damage threshold5, but they also offer increased sample diagnostic capabilities by probing the nonlinear optical response of the specimen.…”

Section: Discussionmentioning

confidence: 99%

Femtosecond-Pulsed Plasmonic Nanotweezers

Roxworthy

Toussaint

2012

Sci Rep

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We demonstrate for the first time plasmonic nanotweezers based on Au bowtie nanoantenna arrays (BNAs) that utilize a femtosecond-pulsed input source to enhance trapping of both Rayleigh and Mie particles. Using ultra-low input power densities, we demonstrate that the high-peak powers associated with a femtosecond source augment the trap stiffness to 2x that of nanotweezers employing a continuous-wave source, and 5x that of conventional tweezers using a femtosecond source. We show that for trapped fluorescent microparticles the two-photon response is enhanced by 2x in comparison to the response without nanoantennas. We also demonstrate tweezing of 80-nm diameter Ag nanoparticles, and observe an enhancement of the second-harmonic signal of ~3.5x for the combined nanoparticle-BNA system compared to the bare BNAs. Finally, under select illumination conditions, fusing of Ag nanoparticles to the BNAs is observed which holds potential for in situ fabrication of three-dimensional, bimetallic nanoantennas.

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Section: Discussionmentioning

confidence: 99%

Femtosecond-Pulsed Plasmonic Nanotweezers

Roxworthy

Toussaint

2012

Sci Rep

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“…In this paper we investigate the local temperature of a laser irradiated single nanoparticle by combining optical tweezers, dark-field illumination and localised surface plasmon resonance (LSPR) spectroscopy [12]. Our method makes use of the temperature dependent refractive index of the surrounding water to correlate the change in the scattering intensity over a fixed spectral window (550-750 nm) with the heating produced at different trapping powers.…”

Section: Introductionmentioning

confidence: 99%

Intrinsic heating in optically trapped Au nanoparticles measured by dark-field spectroscopy

Andres-Arroyo¹,

Wang²,

Toe³

et al. 2015

Biomed. Opt. Express

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Assessing the degree of heating present when a metal nanoparticle is trapped in an optical tweezers is critical for its appropriate use in biological applications as a nanoscale force sensor. Heating is necessarily present for trapped plasmonic particles because of the non-negligible extinction which contributes to an enhanced polarisability. We present a robust method for characterising the degree of heating of trapped metallic nanoparticles, using the intrinsic temperature dependence of the localised surface plasmon resonance (LSPR) to infer the temperature of the surrounding fluid at different incident laser powers. These particle specific measurements can be used to infer the rate of heating and local temperature of trapped nanoparticles. Our measurements suggest a considerable amount of a variability in the degree of heating, on the range of 414-673 K/W, for different 100 nm diameter Au nanoparticles, and we associated this with variations in the axial trapping position.

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“…Conventional techniques like transmission electron microscope (TEM) imaging and dynamic light scattering (DLS) were used to determine the particle dimensions. Optical tweezers can also be used to determine the dimensions of the nanorods using back focal plane interferometry in the same way Pearce et al 10 measure the diameter of trapped nanospheres.…”

Section: Methodsmentioning

confidence: 99%

“…Dark field microscopy can be combined with optical tweezers to measure LSPR spectra on single isolated nanoparticles without compromising the strength of the optical trap. 10 In our setup, we achieve dark field microscopy by using a backscattered light to image the sample. An axicon lens was used to form a ring on light which was imaged onto the back focal plane of the objective.…”

Section: Methodsmentioning

confidence: 99%

Characterisation of Au nanorod dynamics in optical tweezers via localised surface plasmon resonance spectroscopy

et al. 2014

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We present a study of the trapping properties of Au nanorods of different aspect ratios in an optical tweezers and comparison with other characterization techniques like transmission electron microscope (TEM) imaging and dynamic light scattering (DLS). This study provides information on the dynamics and orientation of Au nanorods inside an optical trap based on a time study of their localised surface plasmon resonance (LSPR) features. The results indicate that the orientation of the Au nanorods trapped in our optical tweezers varies with time and LSPR spectra can provide information on the angle of the nanorod with respect to the direction of propagation of the trapping laser.

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Dark-field optical tweezers for nanometrology of metallic nanoparticles

Cited by 28 publications

References 23 publications

Femtosecond-Pulsed Plasmonic Nanotweezers

Femtosecond-Pulsed Plasmonic Nanotweezers

Intrinsic heating in optically trapped Au nanoparticles measured by dark-field spectroscopy

Characterisation of Au nanorod dynamics in optical tweezers via localised surface plasmon resonance spectroscopy

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