title: Laser cooling to quantum degeneracy.
abstract: We report on Bose-Einstein condensation in a gas of strontium atoms, using laser cooling as the only cooling mechanism. The condensate is formed within a sample that is continuously Doppler cooled to below 1  μK on a narrow-linewidth transition. The critical phase-space density for condensation is reached in a central region of the sample, in which atoms are rendered transparent for laser cooling photons. The density in this region is enhanced by an additional dipole trap potential. Thermal equilibrium between the gas in this central region and the surrounding laser cooled part of the cloud is established by elastic collisions. Condensates of up to 10(5) atoms can be repeatedly formed on a time scale of 100 ms, with prospects for the generation of a continuous atom laser.
authors.affiliation: Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, 6020 Innsbruck, Austria.
authors.forename: Simon
authors.initials: S
authors.lastname: Stellmer
authors.forename: Benjamin
authors.initials: B
authors.lastname: Pasquiou
authors.forename: Rudolf
authors.initials: R
authors.lastname: Grimm
authors.forename: Florian
authors.initials: F
authors.lastname: Schreck