Large Area Electrically Tunable Lenses Based on Metasurfaces and Dielectric Elastomer Actuators

Abstract: Tunable optical devices, in particular, varifocal lenses, have important applications in various fields, including imaging and adaptive vision. Recent advances in metasurfaces, which control the wavefront of light using subwavelength-spaced nanostructures, open up new opportunities to replace bulk optical devices, with thin, flat, lightweight devices. We have demonstrated for the first time an electrically tunable flat lens, based on large area metasurfaces combined with a dielectric elastomer actuator having inline transparent electrodes, that is capable of simultaneously performing focal length tuning (>100%) as well as dynamic corrections, including astigmatism and image shift. This offers control versatility to flat optics hitherto only possible in electron microscopes. The water-based transfer process, which we describe, also enables wide compatibility across materials. The combination of metasurface optics and dielectric elastomer actuators enables a new, versatile platform for creating all kinds of tunable optical devices, through the design of tunable phase, amplitude, and polarization profiles.