All-Optical Production of quantum degeneracy and molecular BEC of $^6$Li

TL;DR

This paper reports the all-optical creation of a quantum degenerate Fermi gas and molecular BEC of $^6$Li using direct evaporative cooling in a high-power optical dipole trap, enabling studies of strongly interacting quantum gases.

Contribution

It demonstrates a novel all-optical method to produce quantum degeneracy and molecular BEC of $^6$Li, including the observation of anisotropic expansion in the BEC-BCS crossover.

Findings

Achieved highly degenerate Fermi gas of $^6$Li.

Produced molecular Bose-Einstein condensates.

Observed anisotropic expansion in the BEC-BCS crossover regime.

Abstract

We achieve a highly degenerate and strongly interacting Fermi gas in a mixture of the two lowest hyperfine states of $^6$Li by direct evaporative cooling in a high power crossed optical dipole trap. The trap is loaded from a large atom number magneto-optical trap (MOT) which is realized by a laser system of 2.5-watts intracavity-frequency-doubled light output at 671 nm. With this system, we also demonstrate the production of a molecular Bose-Einstein condensates (mBEC), and observe the anisotropic expansion of Fermi gases in the so-called BEC-BCS crossover regime.