Hollow Bessel beams for guiding atoms between vacuum chambers: a proposal and efficiency study

Abstract

We explore a scheme for guiding cold atoms through a hollow Bessel beam generated by a single axicon and a lens from a 2D magneto-optical trap toward a science chamber. We compare the Bessel beam profiles measured along the optical axis to a numerical propagation of the beam's wavefront, and we show how it is affected by diffraction during the passage through a long narrow funnel serving as a differential pumping tube between the chambers. We derive an approximate analytic expression for the intensity distribution of the Bessel beam and the dipolar optical force acting on the atoms. By a Monte-Carlo simulation based on a stochastic Runge-Kutta algorithm of the motion of atoms initially prepared at a given temperature we show that a considerable enhancement of the transfer efficiency can be expected in the presence of a sufficiently intense Bessel beam.

A conceptual review on Bessel beams

“…The long-range micro-size optical potentials created by BBs and Bessel-like beams can used to trap and guide micro-particles and atomic gas along the beam axis [367][368][369][370][371]. The experimental configuration shown in figure 60, was suggested by J Arlt et al [372] and can be used for particle guiding.…”

Cross polarization of nano-objects located on a flat substrate in the presence of a glass microparticle

“…Then the trap will operate as the so-called atomic guide. The creation of such atomic guides is an actual problem of modern physics, and different technical solutions for these optical traps have been recently suggested in works [36][37][38]. However, all these atomic guides have been formed only on the axes of axially symmetric diffraction-free light beams.…”

Dielectric microcylinder makes a nanocylindrical trap for atoms and ions

“…Therefore, similar traps has been recently developed and corresponding works forms a body of literature (see e.g. in [20][21][22]). However, all these traps, to our knowledge, have been formed only inside the diffraction-free light beams.…”

“…Only a hollow Bessel beam with radial polarization which keeps diffraction-free up to hundreds of microns (from its birthplace at the apex of an axicon lens) grants a really thin and long cylindrical atom trap. Such the trap is demonstrated in work [22]. However, in order to obtain such a magnificent light beam as in work [22], one needs a very expensive optical equipment.…”

“…Such the trap is demonstrated in work [22]. However, in order to obtain such a magnificent light beam as in work [22], one needs a very expensive optical equipment. Meanwhile, our wave beam is a simple superposition of two plane waves.…”