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Abstract: In this paper, we propose a liquid prism based on electrowetting‐on‐dielectric and gravity effect. The device is filled with two immiscible liquids. The conductive liquid is filled in the upper part of the device, and the oil is filled in the bottom of the device. Different from the conventional liquid prism, the density of the conductive liquid is larger than that of the oil. The liquid–liquid interface can form a tilt shape when applied different voltages to the opposite sidewalls. The beam will be deflected when the light passes through the device. Our results show that the tilt angle of the liquid–liquid interface is ~45°, and the light beam can be deflected by 22.2° (−10.9° to +11.3°). The actuation time of the device is ~240 ms. The proposed liquid prism for light beam steering and tracking has potential application in laser directions, telecommunications, and scanners. [ABSTRACT FROM AUTHOR]

• The first annular variable focus Fresnel lens driven by electrowetting. • Each annular region can be independently controlled, and achieve multiple functions. • Suitable for applications as an optical collection device and for achieving uniform beam illumination. Traditional Fresnel lenses can achieve volume diminution by reducing lens material cost, thereby achieving further integration in optical systems. However, the solid Fresnel lenses in being are fixed once they are fabricated due to the limitation of materials, so their optical parameters, like focal length, cannot change. In this paper, we propose a ring-shaped tunable optofluidic Fresnel lens (OFL) based on the electrowetting effect for the first time. Each annular region of the OFL can be independently controlled. By changing the tilt angle of the liquid-liquid interface of each annular region to control the deflection of the beam, the OFL can achieve axial zoom and multi-focus, as well as off-axis zoom. We analyze and establish a theoretical model, provide calculation formulas for the focusing position, and explain the design principle of an annular Fresnel lens driven by electrowetting. A three-annular-regions OFL is fabricated, and we test the focal length of each ring band through experiments to prove the correctness and feasibility of our proposed theory. The OFL can achieve a maximum zoom range of -254 mm to 223 mm. At the same time, we also demonstrate the different working modes of the OFL for applications such as light collection and uniformity. The OFL has a variety of functions, with a lightweight and thin thickness, which meets the expectations of a more and more compact liquid photonic device in the future. We expect this innovative OFL will have extensive applications in various fields, such as optical imaging, lighting engineering, motion tracking, infrared tracking, solar energy collection, and so on. [ABSTRACT FROM AUTHOR]

The conventional electrowetting lens usually has one tunable liquid-liquid (L-L) interface. The shape of L-L interface is deformed to get variable focal length due to electrowetting effect. However, contact angle saturation of the L-L interface is an unavoidable problem which prevents focal length from further changing. Here, we demonstrate an optofluidic lens based on electrowetting liquid piston. The proposed lens has two connected chambers, the piston chamber and the lens chamber to form a closed-loop fluidic system. The electrowetting liquid piston can generate clockwise and counter-clockwise liquid flows, which can make the L-L interface convex and concave. To prove the concept, we fabricate an optofluidic device whose shortest negative and positive focal lengths are ~−17.9 mm and ~18 mm with 5 mm aperture, respectively. The proposed optofluidic lens has large tunable focal length range. Widespread application of such an adaptive lens is foreseeable. [ABSTRACT FROM AUTHOR]

In this paper, we report a prism with two liquid–liquid interfaces based on electrowetting effect. The prism is filled with two immiscible liquids which form two liquid–liquid interfaces. In the device, the filling liquids from the top to the bottom are conductive liquid, oil and conductive liquid. The shape of the two liquid–liquid interfaces will be changed when different voltages are applied to the opposite sidewalls. Our device is capable of wide-angle beam steering and the function of light beam translational. Our results show that the light beam can be deflected by ∼ 22 . 3 ° ( − 11 . 5 ° to + 10 . 8 ° ) and the translational distance is 3.1 mm (−1.5 mm to +1.6 mm). The proposed prism has a wide application in light detection, telecommunications, light alignment and other industrial applications. [ABSTRACT FROM AUTHOR]