Abstract: An optical cavity includes a plurality of mirrors that reflect light along a closed path. First and second mirrors of the plurality of mirrors define an optical axis therebetween. The optical cavity includes first and second lenses located between the first and second mirrors along the optical axis. A mode of the optical cavity has a waist located between the first and second intracavity lenses. Small values of the waist (e.g., <10 microns) produce large cooperativities that relax requirements for the cavity finesse (i.e., reflectivity of the mirrors). The mirrors may be retroreflecting to create a Fabry-Perot cavity. Alternatively, the first and second mirrors may define one segment of a ring cavity. The optical cavity may be used to trap, read, entangle, and drive nonlinear emitters (e.g., atoms, color centers, quantum dots) located near the waist.