Adaptable acylindrical microlenses fabricated by femtosecond laser micromachining

摘要

Microfluidic lenses are a powerful tool for many lab on a chip applications ranging from sensing to detection and also to imaging purpose, with the great advantage to increase the degree of integration and compactness of these micro devices. In this work we present the realization of such a compact microfluidic lens with reconfigurable optical properties. The technique used to realize the device we present is femtosecond laser micromachining followed by chemical etching, which allows to easily fabricate 3D microfluidic devices with an arbitrary shape. Thanks to that it has been possible to easily fabricate different lens made up by cylindrical microchannel in fused silica glasses filled with liquids with a proper refractive index. The optical properties of these devices are tested and shown to be in a good agreement with the theoretical model previously implemented. Furthermore we have also optimized the design of these microlenses in order to reduce the effects of spherical aberrations in the focal region, thus allowing us to obtain a set of different acylindrical microfluidic lenses, whose validation is also reported. In this work the lens adaptability can be achieved by replacing the liquid inside the microchannel, so that we can easily tune the feature of the focused beam. Thus increasing the possible range of applications of these micro optical elements, as an example we report on the validation of the device as a fast integrated optofluidic shutter.