Collimation of a thulium atomic beam by two-dimensional optical molasses

The number of laser cooled and trapped thulium atoms in a magneto-optical trap is increased by a factor of 3 using a two-dimensional optical molasses which collimated the atomic beam before entering a Zeeman slower. A diode laser operating at 410.6 nm was employed to form optical molasses: The laser was heated to 70 °C by a two-step temperature stabilisation system. The laser system consisting of a master oscillator and an injection-locked amplifier emitted more than 100 mW at 410 nm and had a spectral linewidth of 0.6 MHz.