| 1. |
- Volpe, Giovanni, 1979, et al.
(author)
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Roadmap for optical tweezers
- 2023
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In: Journal of Physics-Photonics. - : IOP Publishing. - 2515-7647. ; 5:2
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Journal article (peer-reviewed)abstract
- Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation of objects, ranging from atoms to space light sails. Since the pioneering work by Arthur Ashkin in the 1970s, optical tweezers have evolved into sophisticated instruments and have been employed in a broad range of applications in the life sciences, physics, and engineering. These include accurate force and torque measurement at the femtonewton level, microrheology of complex fluids, single micro- and nano-particle spectroscopy, single-cell analysis, and statistical-physics experiments. This roadmap provides insights into current investigations involving optical forces and optical tweezers from their theoretical foundations to designs and setups. It also offers perspectives for applications to a wide range of research fields, from biophysics to space exploration.
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| 2. |
- Polimeno, P., et al.
(author)
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Gain-Assisted Optomechanical Position Locking of Metal/Dielectric Nanoshells in Optical Potentials
- 2020
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In: Acs Photonics. - : American Chemical Society (ACS). - 2330-4022. ; 7:5, s. 1262-1270
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Journal article (peer-reviewed)abstract
- We investigate gain-assisted optical forces on dye-enriched silver nanoshell in the quasi-static limit by means of a theoretical/numerical approach. We demonstrate the onset of nonlinear optical trapping of these resonant nanostructures in a counter-propagating Gaussian beam configuration. We study the optical forces and trapping behavior as a function of wavelength, particle gain level, and laser power. We support the theoretical analysis with Brownian dynamics simulations that show how particle position locking is achieved at high gains in extended optical trapping potentials. Finally, for wavelengths blue-detuned with respect to the plasmon-enhanced resonance, we observe particle channeling by the standing wave antinodes due to gradient force reversal. This work opens perspectives for gain-assisted optomechanics where nonlinear optical forces are finely tuned to efficiently trap, manipulate, channel, and deliver an externally controlled nanophotonic system.
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| 3. |
- Polimeno, P., et al.
(author)
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Optical tweezers and their applications
- 2018
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In: Journal of Quantitative Spectroscopy & Radiative Transfer. - : Elsevier BV. - 0022-4073. ; 218, s. 131-150
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Journal article (peer-reviewed)abstract
- Optical tweezers, tools based on strongly focused light, enable optical trapping, manipulation, and characterisation of a wide range of microscopic and nanoscopic materials. In the limiting cases of spherical particles either much smaller or much larger than the trapping wavelength, the force in optical tweezers separates into a conservative gradient force, which is proportional to the light intensity gradient and responsible for trapping, and a non-conservative scattering force, which is proportional to the light intensity and is generally detrimental for trapping, but fundamental for optical manipulation and laser cooling. For non-spherical particles or at intermediate (meso)scales, the situation is more complex and this traditional identification of gradient and scattering force is more elusive. Moreover, shape and composition can have dramatic consequences for optically trapped particle dynamics. Here, after an introduction to the theory and practice of optical forces with a focus on the role of shape and composition, we give an overview of some recent applications to biology, nanotechnology, spectroscopy, stochastic thermodynamics, critical Casimir forces, and active matter. (C) 2018 Elsevier Ltd. All rights reserved.
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| 4. |
- Polimeno, P., et al.
(author)
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Position locking of a resonant gain-assisted metallic/dielectric nano-shell in Optical Tweezers
- 2021
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In: Nuovo Cimento C-Colloquia and Communications in Physics. - 2037-4909. ; 44:4-5
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Journal article (peer-reviewed)abstract
- We calculate optical forces on dye-enriched resonant nano-shells in dual-beam Optical Tweezers. We investigate the non-linear gain-assisted enhancement of their optomechanics and study their behaviour through Brownian dynamics simulations. When the wavelength is red detuned with respect to the plasmon resonance, we observe that the particles are efficiently trapped at the laser beam intensity maxima of the dual beam standing wave. Conversely, for blue-detuned wavelengths the nano-shells are channelled through the standing wave antinodes due to the sign reversal of the optical force. This open perspectives for gain-assisted optomechanics where non-linear optical forces are finely tuned to manipulate controlled nano-photonic systems.
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