Microspherical surfaces with predefined focal lengths fabricated using microfluidic capillaries

We demonstrate a technique to fabricate spherical micromirrors with a programmable focal length by microfluidic capillary. Micromirrors with focal lengths of 13 μm, 19 μm, 28 μm, 50 μm, and a flat mirror were fabricated and characterized. These micromirrors show a great ability to converge light into a focal point. This technique also introduces the concept of fabricating and integrating optical components with microfluidic channels.