Fabrication of planar chiral photonic meta-materials on SU- 8 using nanoimprint lithography technique

We present a photonic meta-material with planar dielectric chiral structures on SU-8 realized using nanoimprint lithography (NIL). A Si template with chiral structure arrays was first fabricated by electron beam lithography (EBL) followed by reactive ion etch (RIE). The chiral pattern on the template was then transferred to a SU-8 layer spin coated on Pyrex using an in-house developed press. The imprint property of SU-8 under various pressures and temperatures was systematically studied. The optimized imprint process was successfully applied for the fabrication of planar chiral structure in SU-8. The periodically distributed chiral elements form a photonic crystal with the pitch of 4 μm. Optical diffraction of such kind of periodically arranged chiral structures in SU-8 has been observed for the first time.