Out-of-plane microlens array fabricated using ultraviolet lithography

This letter describes a three-dimensional ultraviolet-lithography (UV-lithography) process for fabricating an out-of-plane microlens array that can be prealigned with other optical components in an integrated optical bench or easily integrated into microfluidic devices. This microlens array is fabricated with a unique UV-lithography technique, and the desired surface profiles are obtained from top rows to lower rows. The microlens’ focal lengths, diameters of focal pads, depths of focus, and surface profiles are measured and reported herein. This microlens array can be prealigned with another microlens array or other optical components on the same substrate to obtain a truly integrated free-space optical bench. In addition, the fill factor of this microlens array approaches 100%.