arXiv subjects

Fedja Oručević

Publications and source records attributed to Fedja Oručević.

3 recordsLinked to original sources

arXiv2026

Absorption imaging of quantum gases near surfaces using incoherent light

We introduce an absorption imaging technique for ultracold gases that suppresses interference fringes and coherence-induced artifacts by reducing the transverse spatial coherence of the imaging light. The method preserves the narrow spectral bandwidth required for resonant absorption imaging and is implemented as a modular extension to standard imaging setups using a rotating diffuser. We demonstrate tunability of the illumination light's coherence without modifying the imaging optics. Using this approach, we achieve reliable imaging of ultracold atomic clouds in micron-scale proximity to complex surfaces, where standing waves, edge diffraction, and speckle severely limit conventional absorption imaging.

cond-mat.quant-gas↗

arXiv2017

Design of Magneto-Optical Traps for Additive Manufacture by 3D Printing

A key element in the study of cold atoms, and their use in emerging quantum technologies, is trapping the atoms in an ultra-high vacuum (UHV) chamber. Many methods have been used to trap atoms including atom chips and magneto-optical traps (MOTs). However, the bulky apparatus, and current-carrying coils, used so far in most MOTs restrict the reduction of power and physical size, as required for quantum technology applications. The advent of 3D printing technology now offers a new route to making MOTs with current paths that can be freely shaped and shrunk to several centimetres, thereby helping to reduce the power consumption and simplify the production of the MOT itself. In this paper, we present designs for 3D printed MOTs and analyse their performance by using COMSOL simulations. We predict that the 3D-printed conductors can create magnetic fields with gradients around 15 G/cm and passing through zero, as required for atom trapping, with Joule heating as low as 0.2 W.

quant-ph↗

arXiv2009

Observation of Cold Collisions between Trapped Ions and Trapped Atoms

We demonstrate a double-trap system well suited to study cold collisions between trapped ions and trapped atoms. Using Yb$^+$ ions confined in a Paul trap and Yb atoms in a magneto-optical trap, we investigate charge-exchange collisions of several isotopes for collision energies down to 400 neV (5 mK). The measured rate coefficient of $6 \times 10^{-10}$ cm$^{3}$s$^{-1}$, constant over four orders of magnitude in collision energy, is in good agreement with that derived from a semiclassical Langevin model for an atomic polarizability of 143 a.u.

physics.atom-ph↗