Nanoimprint and soft lithography for planar photonic meta-materials

This paper proposes to apply nanoimprint and soft lithography to the manufacture of large area planar chiral photonic meta-materials. Both dielectric and metallic chiral structures in nanometre order were replicated by nanoimprint lithography (NIL). To carry out the NIL, a nanofabrication process for imprint templates with chiral features was developed. For the dielectric chiral structures, a single layer of thick hydrogen silsequioxane (HSQ) was used, and for metallic chiral ones a bi-layer PMMA/HSQ technique was employed. The polarization conversion capabilities of planar chiral structures (PCS) imprinted in dielectric materials have been experimentally observed. This indicates that the developed nanoimprint processes in this work have the prospect of manufacturing planar photonic meta-media in high volume at low cost. A hybrid lithography combing nanoimprint and soft lithography is proposed for the constructions of chiral cavities inside dielectric materials.