Two-color magneto-optical trap with small magnetic field for ytterbium

Abstract

We report a two-color magneto-optical trap (MOT) for ytterbium atoms where the slowing and trapping functions are separately performed by the singlet transition light (6s[superscript 2] [superscript 1]S[subscript 0] → 6s6p [superscript 1]P[subscript 1]) and the triplet transition light (6s[superscript 2] [superscript 1]S[subscript 0] → 6s6p [superscript 3]P[subscript 1]), respectively. The two-color MOT is achieved by simultaneously applying laser light on both the broad-linewidth singlet transition and the narrow-linewidth triplet transition. It is highly robust against laser power imbalance even at very low magnetic field gradients, and can operate at magnetic field gradients down to 2 G cm[superscript −1] where a conventional MOT using the singlet transition is unable to trap atoms. We load and trap up to 4.0 × 10[superscript 5] atoms directly from an atomic beam at 700 K.