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Precision in optical micromanipulation is critical for non-invasive, non-contact control of objects with light and for using light to measure forces and torques. We demonstrate the control of birefringent objects over three translational…

Optics · Physics 2025-07-02 Elaina M Wahmann , Catherine M Herne

Light-induced rotation of absorbing microscopic particles by transfer of angular momentum from light to the material raises the possibility of optically driven micromachines. The phenomenon has been observed using elliptically polarized…

We show how it is possible to controllably rotate or align microscopic particles of isotropic nonabsorbing material in a TEM00 Gaussian beam trap, with simultaneous measurement of the applied torque using purely optical means. This is a…

Optical trapping, also known as optical tweezing or optical levitation, is a technique that uses highly focused laser beams to manipulate micro- and nanoscopic particles. In optical traps driven by high-energy pulses, material non-linearity…

Optical trapping, where microscopic particles are trapped and manipulated by light is a powerful and widespread technique, with the single-beam gradient trap (also known as optical tweezers) in use for a large number of biological and other…

Optics · Physics 2007-05-23 T. A. Nieminen , H. Rubinsztein-Dunlop , N. R. Heckenberg

How far a particle moves along the optical axis in a holographic optical trap is not simply dictated by the programmed motion of the trap, but rather depends on an interplay of the trap's changing shape and the particle's material…

Soft Condensed Matter · Physics 2019-10-02 Michael J. O'Brien , David G. Grier

We show that the optical force field in optical tweezers with elliptically polarized beams has the opposite handedness for a wide range of particle sizes and for the most common configurations. Our method is based on the direct observation…

We observe clear precessional motion of highly birefringent liquid crystal (LC) particles trapped in a spherically aberrated optical trap which is built around a tilted refractive index stratified medium. For input circularly polarized…

Optics · Physics 2024-09-04 Sauvik Roy , Nirmalya Ghosh , Ayan Banerjee , Subhasish Dutta Gupta

The spin angular momentum in an elliptically polarized beam of light plays several noteworthy roles in optical traps. It contributes to the linear momentum density in a non-uniform beam, and thus to the radiation pressure exerted on…

Soft Condensed Matter · Physics 2015-06-03 David B. Ruffner , David G. Grier

Magnetic tweezers are crucial for single-molecule and atomic characterization, and biomedical isolation of microparticle carriers. The trapping component of magnetic tweezing can be relying on a magnetic potential well that can confine the…

Applied Physics · Physics 2021-08-11 Yuan Liu , Gungun Lin , Dayong Jin

Roughness and orientational order in thin films of anisotropic particles are investigated using kinetic Monte Carlo simulations on a cubic lattice. Anisotropic next-neighbor interactions between the lattice particles were chosen to mimic…

Soft Condensed Matter · Physics 2022-09-08 Eelco Empting , Nicolas Bader , Martin Oettel

We report the results of studies of torsion effect on the optical birefringence in LiNbO3 crystals. We have found that twisting of those crystals causes a birefringence distribution revealing non-trivial peculiarities. In particular, it has…

Optics · Physics 2015-05-27 Ihor Skab , Yurij Vasylkiv , Viktoriya Savaryn , Rostyslav Vlokh

We report on the observation and measurement of the transfer of transverse angular momentum to birefringent particles several wavelengths in size. A trapped birefringent particle is much larger than the nano-particles systems for which…

Laguerre-Gaussian (LG) beam has orbital angular momentum (OAM). A particle trapped in an LG beam will rotate about the beam axis, due to the transfer of OAM. The rotation of the particle is usually in the same direction as that of the beam…

Optics · Physics 2020-04-15 Yang Li , Lei-Ming Zhou , Nan Zhao

We propose an enantioselective scheme to sort homogeneous chiral particles using optical tweezers. For a certain range of material parameters, we show that a highly focused circularly-polarized laser beam traps particles of a specific…

Optics · Physics 2023-07-19 R. Ali , F. A. Pinheiro , R. S. Dutra , F. S. S. Rosa , P. A. Maia Neto

Optical tweezers are a versatile tool that can be used to manipulate small particles including both motile and non-motile bacteria and cells. The orientation of a non-spherical particle within a beam depends on the shape of the particle and…

Tailored time-dependent variations of the transverse profile together with longitudinal phase shifts of laser beams are studied. It is shown theoretically that a standing wave setup and real-time beam forming techniques (e.g. by…

Optics · Physics 2009-09-29 Ole Steuernagel

Super-oscillating beams can be used to create light spots whose size is below the diffraction limit with a side ring of high intensity adjacent to them. Optical traps made of the super-oscillating part of such beams exhibit superior…

Optics · Physics 2019-05-22 Harel Nagar , Tamir Admon , Doron Goldman , Amir Eyal , Yael Roichman

Optical trapping is a well_established, decades old technology with applications in several fields of research. The most common scenario deals with particles that tend to be centered on the brightest part of the optical trap. Consequently,…

Due to elastic anisotropy, two-dimensional patterning of substrates can promote weak azimuthal alignment of adjacent nematic liquid crystals. Here, we consider how such alignment can be achieved using a periodic square lattice of circular…

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