  Optical cavities are of central importance in numerous areas of physics,
including precision measurement, cavity optomechanics and cavity quantum
electrodynamics. The miniaturisation and scaling to large numbers of sites is
of interest for many of these applications, in particular for quantum
computation and simulation. Here we present the first scaled microcavity system
which enables the creation of large numbers of highly uniform, tunable
light-matter interfaces using ions, neutral atoms or solid-state qubits. The
microcavities are created by means of silicon micro-fabrication, are coupled
directly to optical fibres and can be independently tuned to the chosen
frequency, paving the way for arbitrarily large networks of optical
microcavities.
