Crossed optical cavities with large mode diameters

We report on a compact, ultrahigh-vacuum compatible optical assembly to create large-scale, two-dimensional lattices for use in experiments with ultracold atoms. The consists of an octagon-shaped spacer made from ultra-low-expansion glass, which we optically contact four fused silica cavity mirrors, making it highly mechanically and thermally stable. mirror surfaces are nearly plane-parallel, allows us two perpendicular modes diameters . Such large mode desirable increase the lattice homogeneity, but lead strong angular sensitivities coplanarity between modes. demonstrate procedure precisely position each substrate that achieves deviation Creating at arbitrary visible near-infrared wavelengths requires significant power enhancements overcome limitations available laser power. mirrors have customized low-loss coating enhances set relevant by up 3 orders magnitude..