Large-Area Optical Switch Using Surface-Expandable Liquid Droplets

In this paper, we demonstrate a large-area optical switch using surface-expandable liquid droplets. These droplets are isolated by polymeric grids. The surrounding of the liquid droplets is filled with another immiscible liquid in order to suppress the gravitational effect. To obtain an optical switch, the droplets are doped with dye. In the voltage-off state, the droplets have minimal surface area-to-volume ratio. As a result, the aperture ratio (AR) is maximal. By applying a voltage, the generated dielectric force can expand the surface of the droplets, leading the AR to decrease. At V = 60 V
_rms
, the AR reduces to zero. The optical switch is polarization insensitive. By further optimizing the device structure, this optical switch has promising applications in light shutters, switchable windows, and displays.