Displaceable and focus-tunable electrowetting optofluidic lens

A conventional optofluidic lens usually has one liquid-liquid (L-L) interface, which can be deformed to achieve variable focal length. Such a single lens cannot be used alone to realize optical zooming because its back focal distance keeps changing. Here, we report a novel movable electrowetting optofluidic lens. In comparison with conventional optofluidic lens, our new lens has a different working principle and it can function as an optical zoom lens. The L-L interface can be displaced by a voltage. The object distance and image distance can be adjusted by shifting the L-L interface position to achieve a desired magnification, yet the lens can refocus the image by reshaping the L-L interface with another voltage. Under such condition, only one lens is adequate to realize the zooming functionality. To prove concept, we fabricate an optofluidic lens whose largest movable distance is ~8.3 mm and the zooming ratio is ~1.31. The proposed optofluidic lens greatly simplifies the zoom lens system. Widespread application of such a new adaptive zoom lens is foreseeable.