Methods for determining the polarisability of the fine structure levels in the ground state of the thulium atom

We have calculated the scalar and tensor parts of the polarisabilities of the fine-structure sublevels J = 7/2 and 5/2 of the thulium atom ground state. The static polarisabilities are in a good agreement with the values known from the literature. We also present experimental techniques for measuring the dynamic scalar polarisabilities of these levels at a wavelength of 532 nm. The measured values agree with our calculations within the errors. The results of this work can be used for designing an optical frequency standard based on laser-cooled thulium atoms. (paper)