Tailoring bistability in optical tweezers with vortex beams and spherical aberration

Fuente: arXiv
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Auteurs principaux: da Fonseca, Arthur Luna, Diniz, Kainã, Monteiro, Paula Borges, Pires, Luís Barbosa, Moura, Guilherme Tenório, Borges, Mateus, Dutra, Rafael de Sousa, Ether Jr, Diney Soares, Viana, Nathan Bessa, Neto, Paulo Américo Maia
Format: Preprint
Publié: 2023
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author da Fonseca, Arthur Luna
Diniz, Kainã
Monteiro, Paula Borges
Pires, Luís Barbosa
Moura, Guilherme Tenório
Borges, Mateus
Dutra, Rafael de Sousa
Ether Jr, Diney Soares
Viana, Nathan Bessa
Neto, Paulo Américo Maia
author_facet da Fonseca, Arthur Luna
Diniz, Kainã
Monteiro, Paula Borges
Pires, Luís Barbosa
Moura, Guilherme Tenório
Borges, Mateus
Dutra, Rafael de Sousa
Ether Jr, Diney Soares
Viana, Nathan Bessa
Neto, Paulo Américo Maia
contents We demonstrate a bistable optical trap by tightly focusing a vortex laser beam. The optical potential has the form of a Mexican hat with an additional minimum at the center. The bistable trapping corresponds to a non-equilibrium steady state (NESS), where the microsphere continually hops, due to thermal activation, between an axial equilibrium state and an orbital state driven by the optical torque. We develop a theoretical model for the optical force field, based entirely on experimentally accessible parameters, combining a Debye-type non-paraxial description of the focused vortex beam with Mie scattering by the microsphere. The theoretical prediction that the microsphere and the annular laser focal spot should have comparable sizes is confirmed experimentally by taking different values for the topological charge of the vortex beam. Spherical aberration introduced by refraction at the interface between the glass slide and the sample is taken into account and allows to fine tune between axial, bistable and orbital states as the sample is shifted with respect to the objective focal plane. We find an overall agreement between theory and experiment for a rather broad range of topological charges. Our results open the way for applications in stochastic thermodynamics as it establishes a new control parameter, the height of the objective focal plane with respect to the glass slide, that allows to shape the optical force field in real time and in a controllable way.
format Preprint
id arxiv_https___arxiv_org_abs_2311_04737
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Tailoring bistability in optical tweezers with vortex beams and spherical aberration
da Fonseca, Arthur Luna
Diniz, Kainã
Monteiro, Paula Borges
Pires, Luís Barbosa
Moura, Guilherme Tenório
Borges, Mateus
Dutra, Rafael de Sousa
Ether Jr, Diney Soares
Viana, Nathan Bessa
Neto, Paulo Américo Maia
Optics
Mesoscale and Nanoscale Physics
Statistical Mechanics
We demonstrate a bistable optical trap by tightly focusing a vortex laser beam. The optical potential has the form of a Mexican hat with an additional minimum at the center. The bistable trapping corresponds to a non-equilibrium steady state (NESS), where the microsphere continually hops, due to thermal activation, between an axial equilibrium state and an orbital state driven by the optical torque. We develop a theoretical model for the optical force field, based entirely on experimentally accessible parameters, combining a Debye-type non-paraxial description of the focused vortex beam with Mie scattering by the microsphere. The theoretical prediction that the microsphere and the annular laser focal spot should have comparable sizes is confirmed experimentally by taking different values for the topological charge of the vortex beam. Spherical aberration introduced by refraction at the interface between the glass slide and the sample is taken into account and allows to fine tune between axial, bistable and orbital states as the sample is shifted with respect to the objective focal plane. We find an overall agreement between theory and experiment for a rather broad range of topological charges. Our results open the way for applications in stochastic thermodynamics as it establishes a new control parameter, the height of the objective focal plane with respect to the glass slide, that allows to shape the optical force field in real time and in a controllable way.
title Tailoring bistability in optical tweezers with vortex beams and spherical aberration
topic Optics
Mesoscale and Nanoscale Physics
Statistical Mechanics
url https://arxiv.org/abs/2311.04737