An ytterbium quantum gas microscope with narrow-line laser cooling

Abstract

We demonstrate site-resolved imaging of individual bosonic ${}^{174}\mathrm{Yb}$ atoms in a Hubbard-regime two-dimensional optical lattice with a short lattice constant of 266 nm. To suppress the heating by probe light with the ^1 S _0 – ^1 P _1 transition of the wavelength λ = 399 nm for high-resolution imaging and preserve atoms at the same lattice sites during the fluorescence imaging, we simultaneously cool atoms by additionally applying narrow-line optical molasses with the ^1 S _0 – ^3 P _1 transition of the wavelength λ = 556 nm. We achieve a low temperature of $T=7.4(13)\ \mu {\rm{K}}$ , corresponding to a mean oscillation quantum number along the horizontal axes of 0.22(4) during the imaging process. We detect, on average, 200 fluorescence photons from a single atom within a 400 ms exposure time, and estimate a detection fidelity of 87(2)%. The realization of a quantum gas microscope with enough fidelity for Yb atoms in a Hubbard-regime optical lattice opens up the possibilities for studying various kinds of quantum many-body systems such as Bose and Fermi gases, and their mixtures, and also long-range-interacting systems such as Rydberg states.

Keywords

• cold atoms
• optical lattice
• laser cooling
• quantum gas microscope
• 67.85.Hj
• 07.60.Pb