Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting

Today, freeform micro-optical structures are desired components in many photonic and optical applications, such as lighting and detection systems, due to their compactness, ease of system integration, and superior optical performance. The high complexity of a freeform structure’s arbitrary surface profile and the need for high throughput upon fabrication require sophisticated approaches for their integration into a manufacturing process. In this paper, we discuss a smart fabrication process of freeform micro-optical elements that ranges from their design by optical simulations to their cost-efficient fabrication by maskless laser direct write lithography (MALA) and replication from the as-fabricated master by imprinting. Aided by profilometry and optical microscopy, the fidelity of the fabricated freeform micro-optical elements to the design is characterized. Finally, the light intensity distribution on a target plane affected by the freeform micro-optical element illuminated with a light-emitting diode is determined and compared with the predicted one.