Vibration-insensitive mounting of a reference cavity for an optical clock

We report on a novel vibration-insensitive mounting design of the reference cavity used for stabilization of the clock laser in an optical frequency standard. The cavity is supported in the horizontal symmetry plane on four supporting points while the optical axis is oriented horizontally. The positions of the points have been optimized by finite element analysis. This has resulted in a measured sensitivity to acceleration of 1.5 kHz/(m/s
²
) in the vertical and 14 kHz/(m/s
²
) in the horizontal direction. This is a reduction of two orders of magnitude in the vertical and one order of magnitude in the horizontal direction compared to the support from below.