High-Sensitivity In situ Fluorescence Imaging of Ytterbium Atoms in a Two-Dimensional Optical Lattice with Dual Optical Molasses

Abstract

We developed a dual molasses technique which enabled us to perform high-sensitivity in situ fluorescence imaging of ytterbium (Yb) atoms in a two-dimensional optical lattice prepared in a thin glass cell. This technique successfully combines two different kinds of optical molasses for Yb atoms, that is, the one using the 1S0–1P1 transition which provides high-resolution in the in situ fluorescence imaging and the other using the 1S0–3P1 transition for cooling the atoms in the optical lattice. We performed in situ imaging of 174Yb atoms and could observe a Moiré pattern with a period of about 6 µm produced by the molasses beam with 556 nm and the optical lattice with 532 nm, which implies that the temperature was kept below the lattice depth during the fluorescence imaging. The number of photons per atom is estimated to be enough for single atom detection with our imaging system. This result is quite promising for the realization of an Yb quantum gas microscope.