arXiv subjects

Vladyslav V. Ivanov

Publications and source records attributed to Vladyslav V. Ivanov.

6 recordsLinked to original sources

arXiv2022

Compact optical grating compressor

A novel design of a grating-based optical pulse compressor is proposed. The proposed compressor provides a large group delay dispersion while keeping the compressor linear size small. The design of the proposed compressor is based on a traditional Treacy compressor with a straightforward modification of inserting two lenses between the compressor's gratings. This simple alternation aims to substantially increase group delay dispersion of the compressor or alternatively to decrease the compressor size while maintaining its group delay dispersion. A theoretical description of the enhanced compressor has been developed in the paraxial approximation. A detailed numerical model has been built to calculate the compressor parameters more accurately. These theoretical studies have revealed that the enhanced optical compressor provides a significant increase in the group delay dispersion compared to a standard Treacy compressor.

physics.optics↗

arXiv2014

Continuous loading of an atom beam into an optical lattice

I propose a method of deceleration and continuous loading of an atom beam into a far-off-resonance optical lattice. The loading of moving atoms into a conservative far-off-resonance potential requires the removal of the atom's excess kinetic energy. Here this is achieved by the Sisyphus cooling method, where a differential lattice-induced ac Stark shift is utilized. The proposed method is described for the case of ytterbium atoms. Numerical simulations demonstrate the possibility of reaching cold and dense samples in a continuous manner on the example of ytterbium atoms.

physics.atom-ph↗

arXiv2012

Study of surface potentials using resonant tunneling of cold atoms in optical lattices

We study a feasibility of precision measurements of surface potentials at micrometer distances using resonant tunneling of cold atoms trapped in vertical optical lattices. A modulation of an amplitude of the lattice potential induces atomic tunneling among the lattice sites. The resonant modulation frequency corresponds to a difference of potential energy between latices sites which is defined by external force i.e. gravity. The vicinity of the surface alters the external potentials, and hence the resonant frequency. Application of this method allows accurate study of Casimir-type potentials and improvement of the present experimental validity of the Newtonian gravitational potential at the distance range of 5 - 30 micrometers.

physics.atom-ph↗

arXiv2011

Laser-driven Sisyphus cooling in an optical dipole trap

We propose a novel Sisyphus cooling scheme for atoms confined in a far off resonance optical dipole trap. Utilizing the differential trap-induced AC Stark shift, two electronic levels of the atom are resonantly coupled by a cooling laser preferentially near the trap bottom. After absorption of a cooling photon, the atom loses energy by climbing the steeper potential, and then spontaneously decays preferentially away from the trap bottom. The proposed method is particularly suited to cooling alkaline-earth-like atoms where two-level systems with narrow electronic transitions are present. Numerical simulations for the cases of $^{88}$Sr and $^{174}$Yb demonstrate the expected recoil and Doppler temperature limits. The method requires a relatively small number of scattered photons and can potentially lead to phase space densities approaching quantum degeneracy in sub-second timescales.

physics.atom-ph↗

arXiv2011

Quantum Degenerate Mixture of Ytterbium and Lithium Atoms

We have produced a quantum degenerate mixture of fermionic alkali 6Li and bosonic spin-singlet 174Yb gases. This was achieved using sympathetic cooling of lithium atoms by evaporatively cooled ytterbium atoms in a far-off-resonant optical dipole trap. We observe co-existence of Bose condensed (T/T_c~0.8) 174Yb with 2.3*10^4 atoms and Fermi degenerate (T/T_F~0.3) 6Li with 1.2*10^4 atoms. Quasipure Bose-Einstein condensates of up to 3*10^4 174Yb atoms can be produced in single-species experiments. Our results mark a significant step toward studies of few and many-body physics with mixtures of alkali and alkaline-earth-like atoms, and for the production of paramagnetic polar molecules in the quantum regime. Our methods also establish a convenient scheme for producing quantum degenerate ytterbium atoms in a 1064nm optical dipole trap.

cond-mat.quant-gas↗

arXiv2011

Sympathetic cooling in an optically trapped mixture of alkali and spin-singlet atoms

We report on the realization of a stable mixture of ultracold lithium and ytterbium atoms confined in a far-off-resonance optical dipole trap. We observe sympathetic cooling of 6Li by 174Yb and extract the s-wave scattering length magnitude |a6Li-174Yb| = (13 \pm 3)a0 from the rate of inter-species thermalization. Using forced evaporative cooling of 174Yb, we achieve reduction of the 6Li temperature to below the Fermi temperature, purely through inter-species sympathetic cooling.

physics.atom-ph↗