Integrated on-chip lens applied to microfluidic chips

The optical signal on microfluidic chip is hard to be collected. To improve the excitation power and collection efficiency, we introduced a simple, inexpensive fabrication method to increase the couple rate of optical fiber. This small element is a polymer and air integrated microlens that can improve the optical signal detection. Compared to other established protocols, this procedure allows a simple, miniaturizing and inexpensive microlens fabrication with high reproducibility. The air microlens was produced by using direct lithograph of SU-8 resist to reduce the beam divergence of optical fiber. Owing to its ability to achieve customized microlens for specific applications, this technique can be used in a variety of applications, such as a blood cell counting system based on microfluidic chip.