Microfabricated high-finesse optical cavities for atom chips

Optical tools have proved immensely valuable for experiments in atomic physics. Here we present a novel type of optical resonator intended for integration on atom chips. 1 One mirror of the microcavity is a concave mirror with a radius of curvature of 180µm, and is formed on the surface of a silicon wafer by means of isotropic etching. The second mirror is a dielectric multilayer film, attached to the cleaved tip of a single-mode optical fibre. The fibre is then used to couple light into and out of the resonator. We have fabricated large arrays of mirror templates on silicon in a single etching step. This allows us to create multiple cavities using a single chip. We have achieved Q-factors of up to 10 6 and finesse values of over 5000, indicating that our devices will enable the detection of single atoms with high probability. Together with their small mode volume, the high Q- and finesse values of these devices bring us close to the regime in which the atom and the cavity mode are strongly coupled, leading to applications in quantum information processing. We will report on the creation of multiple cavities on one chip, as well as on our progress towards the detection of small numbers of atoms using these devices.