Liquid prism for beam tracking and steering

We propose a liquid prism based on electrowetting for wide-angle beam tracking and steering. Two transparent cubic cells which are filled with two immiscible liquids are stacked together to form the device. The two cubic cells function as two optical prisms. Via eletrowetting, we successfully control the liquid–liquid interface by changing the applied voltage on the opposite sidewalls. The device is capable of wide-angle beam tracking and steering. The experiment shows that the device can deflect and steer the light through an angle of ∼19.9 deg (+10.4 deg to −9.5 deg), and the total response time is ∼202 ms. The proposed liquid prism has a potential application such as free-space optical communications and laser detection electrowetting solar cells.