Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Blue laser cooling transitions in Tm I   We have studied possible candidates for laser cooling transitions in
$^{169}$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
$4\textrm{f}^{13}6\textrm{s}^2(^2\textrm{F}_0)(J_g=7/2)$ to upper states
$4\textrm{f}^{12}(^3\textrm{H}_5)5\textrm{d}_{3/2}6\textrm{s}^2(J_e=9/2)$ at
410.6 nm and
$4\textrm{f}^{12}(^3\textrm{F}_4)5\textrm{d}_{5/2}6\textrm{s}^2(J_e=9/2)$ 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 $2\cdot10^{-5}$ and can be used for efficient laser cooling of
$^{169}$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 $7(2)$ s$^{-1}$ for the rate of magnetic-dipole transition
at 1.14 $\mu$m between the fine structure levels
$(J_g=7/2)\leftrightarrow(J'_g=5/2)$ of the ground state which can be
considered as a candidate for applications in atomic clocks.

32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph