Diffraction-limited optical dipole trap with a hollow optical fiber

Abstract

We propose a novel three-dimensional diffraction-limited far-off-resonance optical dipole trap (DFORT) for neutral atoms operating in the Lamb–Dicke regime. Such a microscopic DFORT is generated by the diffracted LP01 mode of a hollow-core optical fiber near the fiber facet. For 87Rb and 133Cs atoms, we estimate that with a 100-mW trap-laser power, a cigar-shaped far-off-resonance optical dipole trap provides potential depth U0≃10 mK, radial (axial) trap frequency fr≃100 kHz(fz≃10 kHz), and trap volume Vtrap≃104λ3. The DFORT has the unique feature of a tightly focused trap with a large trap volume and convenient loading and cooling of the precooled atoms, which may be useful for optical Bose–Einstein condensation. A DFORT may be also operated as an elongated one-dimensional optical trap.