Circular dielectric liquid iris.

We demonstrate a liquid iris diaphragm using dielectric force, enabling its aperture to vary from 4 mm at the resting state to 1.5 mm at 160 V(rms). The liquid iris is a packaged optical component comprised of transparent oil, opaque ink, and a set of driving electrodes on a glass substrate. The iris aperture shrinks with the dielectric force, which is exerted on the interface between the two nonconductive liquids. The transmittance was measured to exceed 85% with no antireflection coatings over the spectrum of visible light. The maximum electric power consumed is measured to be 5.7 mW.