Nanoimprint technology for nano-structured optical devices

We present the fabrication method for various nano-structured optical devices such as a nanowire grid polarizer, a Bragg grating filter, and an optical ring resonator to demonstrate feasibility of nanoimprint technology for manufacturing nanoscale optical devices. A 50 nm half-pitch nanowire grid polarizer was successfully fabricated by using nanoimprint lithography (NIL), of which extinction ratio is twice higher than that of the commercially available 70 nm half-pitch one. Generation of the uniform and seamless 50 nm half-pitch metal gratings over the large area is impossible or impractical with lithographic techniques other than NIL. The Bragg grating filter and optical ring resonator were fabricated in low-loss optical polymers simply by means of a single imprint process which does not require conventional photolithography and reactive ion etching processes. This work demonstrates the possibility of a low cost production of planar waveguide circuits for optical communications.