Deep Laser Cooling of Thulium Atoms to Sub-μK Temperatures in Magneto-Optical Trap

Deep laser cooling of atoms, ions, and molecules facilitates the study of fundamental physics as well as applied research. In this work, we report on the narrow-line laser cooling of thulium atoms at the wavelength of 506.2nm with the natural linewidth of 7.8kHz, which widens the limits of atomic cloud parameters control. Temperatures of about 400nK, phase-space density of up to 3.5x10(-4) and 2x10(6) number of trapped atoms were achieved. We have also demonstrated formation of double cloud structure in an optical lattice by adjusting parameters of the 506.2nm magneto-optical trap. These results can be used to improve experiments with BEC, atomic interferometers, and optical clocks.