Direct replication of a glass micro Fresnel zone plate array by laser irradiation using an infrared transmissive mold

It is not yet possible to fabricate micrometer-scale, glass optical components with nanometer-scale precision. Glass thermal imprinting enhances production efficiency. However, dimensional changes caused by shrinkage are inevitable because of phase transitions. Replication is very difficult when high-level pitch precision is essential. We used an infrared-transparent silicon mold and a CO₂ laser to perform replica-type, thermal surface texturing at the nanoscale level; we analyzed a glass Fresnel zone plate array to this end. The Fresnel zone plate array was 10 × 10 mm² in area and featured a 20 × 20 array. The individual Fresnel zone plate diameter was 500 µm and had 21 rings of minimum linewidth 2.9 µm and height 737 nm.