Monolithic polymer microlens arrays with high numerical aperture and high packing density.

This work reports a novel method for monolithic fabrication of high numerical aperture polymer microlens arrays (high-NA MLAs) with high packing density (PD) at wafer level. The close-packed high-NA MLAs were fabricated by incorporating conformal deposition of ultrathin fluorocarbon nanofilm and melting the cylindrical polymer islands. The NA and PD of hemispherical MLAs with a hexagonal arrangement increase up to 0.6 and 89%, respectively. The increase of NA enhances the lens transmission securing the beam width down to 1.1 μm. The close-packed high-NA MLAs enable high photon collection efficiency with signal-to-noise ratio greater than 50:1.