On the motion control of microparticles by means of an electromagnetic field increasing with time for spectroscopic applications

A. Ch. Izmailov

The possibility of controlling the motion of microparticles by means of external electromagnetic fields (nonresonance laser radiation, in particular) that induce potential wells for such particles, which are characterized by fixed spatial distribution but deepen over time to a certain level, are analyzed. It is assumed that the particles are located in high vacuum and are affected by nondissipative external forces. Slowing down of relatively fast particles when they pass through the discussed potential wells is shown. Such slowing down of particles is demonstrated using a nonresonance laser beam with intensity increasing over time as an example. Specific features of particle dynamics in the electromagnetic fields under consideration in the case of a one-dimensional rectangular potential well are studied in detail based on simple analytical relations derived from the fundamental equations of classical mechanics. The methods of particle cooling and localization demonstrated in the present work can substantially increase spectroscopy resolution of various microparticles, including, under certain conditions, atoms and molecules.

DOI

Transport of a spherical transparent nanoparticle by radiation forces in the field of a Gaussian laser beam

A. A. Afanas’ev, L. S. Gaida , D. V. Guzatov, D. V. Novitski, E. V. Matuk

The motion of a spherical transparent nanoparticle under the influence of radiation forces in the field of a Gaussian laser beam is investigated based on solution of Langevin equation. Expressions governing transverse and longitudinal velocities of the nanoparticle under the action of gradient and scattering forces are derived and analyzed. The possibility of spatial separation of nanoparticles having different sizes and optical properties is discussed.

DOI

Trapping of classical particles by an electromagnetic potential well deepening over time

A. Ch. Izmailov

On the basis of fundamental relations of classical mechanics, we established a mechanism of trapping and localization of sufficiently slow particles by an electromagnetic potential well that becomes deeper over time (up to a certain limit). It is assumed that these particles are contained in high vacuum, and acting upon them forces are not dissipative. Such potential wells can be created by means of an electromagnetic field (nonresonance radiation, in particular) with fixed spatial distribution and nondecreasing over time electric field strength. Trapping and localization of particles in such electromagnetic traps, which takes place due to gradient forces, is analyzed for laser beams with typical intensity distribution. The obtained results can be used in high-resolution spectroscopy of different particles, including, in some cases, atoms and molecules.

DOI