Two-stage laser cooling and optical trapping of thulium atoms

Abstract

We propose to use the magnetic-dipole transition at coupling two ground state fine-structure components of thulium (Tm), as a 'clock transition' in optical clocks. We have demonstrated first stage laser cooling of Tm atoms down to a temperature of 25 K using a strong transition at and we have also shown preliminary results for second stage cooling using a weaker transition at (natural linewidth γG = 350 kHz). Laser cooled atoms have been trapped in an optical dipole trap and in a 1D optical lattice operating near 532 nm.