Modeling and Characterization of Micro Optofluidic Lenses With Short Focal Length

In this paper, fluidic models of liquid-core liquid-cladding lens formed in a circular chamber are reported. The models cover two cases: the circular chamber is symmetrical and asymmetrical to the channel axis. Experiments were also carried out to verify our models. The results agree well with the theoretical analysis. The test device with a circular lens chamber with 1-mm diameter and 100-μm height was fabricated in PDMS. The design of a circular chamber is demonstrated to develop a perfect arc shape of the lens interface, which can be mathematically pre-defined. The focusing abilities of lens formed in these two different geometries are compared. We found that the asymmetrical design, in which the channel is offseted from the axis of chamber, can develop a lens with shorter focal length. This design has an important significance for on-chip focusing.