Relief gratings and microlenses fabricated with silicone.

Divergent microlenses and low-spatial-frequency interference gratings have been fabricated in low-cost silicone layers. The size of the microlenses ranges from approximately 1 mm to 100 microm while spatial frequencies of interference gratings range from 4 to 18 l/mm. The fabrication method involves the recording of spatial distributions of mid-IR light. At recording time silicone layers are in a gel state. Then layers are cured by heat. The final silicone layers are transparent and rigid.