Versatile Size and Shape Microlens Arrays With High Numerical Apertures

We present close-packed microlens arrays (MLAs) with high numerical aperture (NA) over a large range of dimensions based on glass blowing process and replication method. Polydimethylsiloxane (PDMS) MLAs with diameters from (50~mu ) m to 1 mm and a high NA of 0.37 (maximum achievable NA for a PDMS plano-convex lens) are demonstrated, which are difficult to achieve with the conventional methods for large microlenses. In addition, MLAs with various fill-factors up to 96.1% and different base shapes are demonstrated. By adjusting the cavity depth and the chamber pressure, the ratio of sag height and diameter can be further adjusted.