Electrically tunable lens with a non-monotonic wavefront control capability.

We describe an electrically tunable liquid crystal lens that can produce a rich variety of wavefronts, including sombrero-type (non-monotonic) phase modulation, enabling the focusing of light into a ring-shaped intensity distribution. The lens can also generate axicons or standard spherical lenses with a bipolar response (providing both positive and negative optical powers). The design of the lens requires only a single-step lithography process, dramatically simplifying its manufacturing. We describe various driving modes of this lens and present the first experimental results and discuss its possible applications in miniature cameras and microscopes. We think that this device can revolutionize the optical design in many areas of photonics.