Related papers: Measurement of the total optical angular momentum …
We have developed a scheme to measure the optical torque, exerted by a laser beam on a phase object, by measuring the orbital angular momentum of the transmitted beam. The experiment is a macroscopic simulation of a situation in optical…
In recent years there has been an explosive development of interest in the measurement of forces at the microscopic level, such as within living cells, as well as the properties of fluids and suspensions on this scale, using optically…
We present a method to measure the optical torque applied to particles of arbitrary shape held in an optical trap, inferred from the change of angular momentum of light induced by the particle. All torque components can be determined from a…
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…
The expression for the total angular momentum carried by a laser optical vortex beam, splits, in the paraxial approximation, into two terms which seem to represent orbital and spin angular momentum respectively. There are, however, two very…
Optical tweezers are widely used as a highly sensitive tool to measure forces on micron-scale particles. One such application is the measurement of the electric charge of a particle, which can be done with high precision in liquids, air, or…
Optical vortex beams carry orbital angular momentum and thus exert torque on illuminated objects. A dielectric microtool - a microbarbell - is used in a two-laser optical tweezers to measure the torque of a focused optical vortex. The tool…
Optical tweezers are highly versatile laser traps for neutral microparticles, with fundamental applications in physics and in single molecule cell biology. Force measurements are performed by converting the stiffness response to…
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…
Rotational optical tweezers are used to probe the mechanical properties of unknown microsystems. Quantifying the angular trap stiffness is essential for interpreting the rotational dynamics of probe particles. While methods to determine…
A key element in the generation of optical torque in optical traps, which occurs when electromagnetic angular momentum is transferred from the trapping beam to the trapped particle by scattering, is the symmetries of the scattering particle…
Optically levitated dielectric nanoparticles have become valuable tools for precision sensing and quantum optomechanical experiments. To predict the dynamic properties of a particle trapped in an optical tweezer with high fidelity, a tool…
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…
The optical forces in optical tweezers can be robustly modeled over a broad range of parameters using generalsed Lorenz-Mie theory. We describe the procedure, and show how the combination of experimental measurement of properties of the…
We demonstrate an optical system that can apply and accurately measure the torque exerted by the trapping beam on a rotating birefringent probe particle. This allows the viscosity and surface effects within liquid media to be measured…
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…
It is important to evaluate the total spin angular momentum of alkali-metal atoms if the atoms serve as a reservoir of angular momenta. We use an absorption-monitoring technique to measure <Fz>, i.e., the expectation values of the…
We demonstrate a new method for determining the radius of micron-sized particles trapped by a vortex laser beam. The technique is based on measuring the rotation experienced by the center of mass of a microsphere that is laterally displaced…
Photons carry linear momentum, and spin angular momentum when circularly or elliptically polarized. During light-matter interaction, transfer of linear momentum leads to optical forces, while angular momentum transfer induces optical…
The force exerted on nanoparticles and atomic clusters by fast passing electrons like those employed in transmission electron microscopes are calculated and integrated over time to yield the momentum transferred from the electrons to the…