We produce Bose-Einstein condensates of 162 Dy atoms employing an innovative technique based on a resonator-enhanced optical trap that allows efficient loading from the magneto-optical trap. We characterize the scattering properties of the ultracold atoms for magnetic fields between 6 and 30 G. In addition to the typical chaotic distribution of narrow Feshbach resonances in Lanthanides, we discover two rather isolated broad features at around 22 G and 27 G. A characterization using the complementary measurements of losses, thermalization, anisotropic expansion and molecular binding energy points towards resonances of predominant s-wave character. Such resonances will ease the investigation of quantum phenomena relying on the interplay between dipole and contact interactions. 34.50.Cx, 37.0.De, 67.85.Hj Dipolar atomic Bose-Einstein condensates (dBEC) are proving to be excellent platforms for the study of a range of quantum phenomena relying on the interplay between the anisotropic long-range dipole-dipole interaction and the isotropic contact one. Recent experiments with dBEC demonstrated the existence of an unexpected quantum liquid phase, emerging for attractive mean-field interactions and stabilized by quantum fluctuations [1][2][3][4], showed the possibility to study lattice physics beyond the standard Bose-Hubbard model [5], and revealed first signatures of peculiar roton excitations [6] and scissors oscillations [7]. All these observations rely on the large magnetic moment available in Lanthanides, and require a fine control of the relative strength of dipolar and contact interactions. However, so far only very narrow Feshbach resonances, with widths of the order of tens of mG, have been employed to this scope. In fact, the complex electronic structure of such atoms, responsible for their large magnetic dipole moment, also leads to a strong anisotropy of the van der Waals interaction, which gives rise to an extremely dense chaotic distribution of narrow Feshbach resonances [8,9]. Dysprosium is the most magnetic atom available, whose magnetic dipole moment of 9.93 µ B results in a dipolar length a dd 130 a 0 . In the ground state of 164 Dy, besides the chaotic spectrum, two very broad Feshbach resonances with ∆ 30 G have been observed and characterized [10]. Their practical use is however questionable, since the resonances poles are surrounded by many narrow resonances. The other bosonic isotope, 162 Dy, has been characterized only up to 6 G: only narrow resonances appear, with the largest width around 25 mG [11,12].In this work we report on the production of a dBEC of 162 Dy and on the exploration of the resonance spec- * lucioni@lens.unifi.it trum up to 30 G. The BEC is produced employing a large-volume optical trap enhanced by an in-vacuum optical resonator, which allows an efficient capture of atoms from the magneto-optical trap (MOT) using a low-power single-mode laser. This technique was so far used only with alkalis and Yb atoms [13,14]; the application to dipolar Lanthanides is particularly intere...

Abstract. In the domain of quantum degenerate atomic gases, much interest has been raised recently by the use of Lanthanide atoms with large magnetic moments, in particular Dysprosium and Erbium. These species have been successfully brought to quantum degeneracy and are now excellent candidates for quantum simulations of physical phenomena due to long-range interactions. In this short article, we report on the progresses in the construction of a new experiment on Bose-Einstein condensation of Dysprosium atoms. After completing the vacuum and the laser setups, a magneto-optical trap on the narrow 626 nm 162 Dy transition has been realized and characterized. The prospects for future experiments are briefly discussed.Quantum degenerate dipolar systems are nowadays among the most interesting systems in quantum physics because they provide, to a very large extent, a clean and controlled experimental environment where long-range, anisotropic interactions can be finely tuned against short-range, isotropic ones. Although the dipolar interaction strength is much lower than that achievable in molecular systems, atomic samples are suitable to study a variety of phenomena thanks to the absence of large inelastic losses and to the immediacy of application of well-developed experimental techniques. Dipolar interactions in ultracold atoms, according to theoretical predictions [1,2,3], give rise to a wealth of peculiar quantum phenomena and exotic quantum phases, encompassing super-solids, quasi-crystals, frustrated crystals and self-assembled structures. These phenomena are due to the combination of the long-ranged and anisotropic nature of such interactions. Dipolar gases in optical lattices may widen the existing possibilities for the quantum simulation of condensed matter-like physics [4,5].Among open-shell Lanthanides having the largest magnetic interaction, quantum degeneracy has been recently attained for Dysprosium [6,7] and Erbium [8,9], both nicely providing bosonic and fermionic isotopes in large natural abundance. These systems have shown a very rich collisional dynamics [10,11,12] due to their large spin and orbital angular momentum and, most of all, spectacular phase transitions [13,14]