7 research outputs found
Magneto-Optical Trap for Thulium Atoms
Thulium atoms are trapped in a magneto-optical trap using a strong transition
at 410 nm with a small branching ratio. We trap up to atoms at
a temperature of 0.8(2) mK after deceleration in a 40 cm long Zeeman slower.
Optical leaks from the cooling cycle influence the lifetime of atoms in the MOT
which varies between 0.3 -1.5 s in our experiments. The lower limit for the
leaking rate from the upper cooling level is measured to be 22(6) s. The
repumping laser transferring the atomic population out of the F=3 hyperfine
ground-state sublevel gives a 30% increase for the lifetime and the number of
atoms in the trap.Comment: 4 pages, 6 figure
Zeeman slowing of thulium atoms
We demonstrate laser slowing of a hot thulium atomic beam using the nearly
closed cycling transition
at 410.6 nm. Atoms are decelerated to velocities around 25 m/s by a 40 cm
Zeeman slower. The flux of slowed atoms is evaluated as . The experiment explicitly indicates the
possibility of trapping Tm atoms in a magneto-optical trap.Comment: 3 pages, 4 figure
Blue laser cooling transitions in Tm I
We have studied possible candidates for laser cooling transitions in
Tm in the spectral region 410 -- 420 nm. By means of saturation
absorption spectroscopy we have measured the hyperfine structure and rates of
two nearly closed cycling transitions from the ground state
to upper states
at
410.6 nm and
at
420.4 nm and evaluated the life times of the excited levels as 15.9(8) ns and
48(6) ns respectively. Decay rates from these levels to neighboring
opposite-parity levels are evaluated by means of Hartree-Fock calculations. We
conclude, that the strong transition at 410.6 nm has an optical leak rate of
less then and can be used for efficient laser cooling of
Tm from a thermal atomic beam. The hyperfine structure of two other
even-parity levels which can be excited from the ground state at 409.5 nm and
418.9 nm is also measured by the same technique. In addition we give a
calculated value of s for the rate of magnetic-dipole transition
at 1.14 m between the fine structure levels
of the ground state which can be
considered as a candidate for applications in atomic clocks.Comment: 8 pages, 5 figure