Buffer gas loaded magneto-optical traps for Yb, Tm, Er and Ho

Abstract

Direct loading of lanthanide atoms into magneto-optical traps (MOTs) from a very slow cryogenic buffer gas beam source is achieved, without the need for laser slowing. The beam source has an average forward velocity of 60– $70\;{\rm m}\;{{{\rm s}}^{-1}}$ and a velocity half-width of $\sim 35\;{\rm m}\;{{{\rm s}}^{-1}}$ , which allows for direct MOT loading of Yb, Tm, Er and Ho. Residual helium background gas originating from the beam results in a maximum trap lifetime of about 80 ms (with Yb). The addition of a single-frequency slowing laser applied to the Yb in the buffer gas beam increases the number of trapped Yb atoms to $1.3\left( 0.7 \right)\times {{10}^{8}}$ with a loading rate of $2.0\left( 1.0 \right)\times {{10}^{10}}\;{\rm atoms}\;{{{\rm s}}^{-1}}$ . Decay to metastable states is observed for all trapped species and decay rates are measured. Extension of this approach to the loading of molecules into a MOT is discussed.

Keywords

• magneto-optical trap
• buffer gas beam source
• laser cooling
• 37.20.+j
• 37.10.Gh
• 07.20.Mc