Optical waveguide systems and methods are described. In one aspect, a display system includes a planar acoustic cavity having a fundamental resonant acoustic mode. The acoustic cavity includes an array of optical waveguides and an array of acoustic transducers. Each of the optical waveguides includes a respective cladding surrounding a liquid-filled core. The array of acoustic transducers is operable to generate acoustic waves that propagate in the acoustic cavity across the cores of the optical waveguides.
