Design and characteristics of tunable in-plane optofluidic lens actuated by viscous force

In this Letter, we report a tunable in-plane optofluidic lens based on a new regulation method. The viscous force (VF) adjusts a 68# white mineral oil-air interface and focal length (f). Two glass plates bonded by ultraviolet adhesive strips form a lens chamber. Liquid enters the chamber by capillary action and forms a convex interface due to VF. As the liquid filling amount increases, VF is enhanced, and the interface deforms. Because of the uneven VF, interface is aspheric, which can reduce the lens aberration. Bendings on both sides of the interface caused by edge effect lead to an even polynomial profile of the entire interface, and they can be used for aberration correction of an in-plane spherical reflector. Experiments demonstrate the continuous tuning of f from 17.7 to 45.1 mm. The positive longitudinal spherical aberration (LSA) is effectively suppressed below 0.078 when f<35.5mm. Interface with a large negative LSA is used for spherical reflector aberration correction. Simulation results proved that the light spot improvement rate is>90%, and the maximum reached 99%.