Polymer photonic devices fabricated by "reverse" and nanoimprint techniques

Three-dimensional superstructures are fabricated by means of "reverse" and nanoimprint lithography techniques. The nanoimprint lithography technique is based on the deformation of a thin polymer film with a rigid stamp. First the stamp is pressed into a thin polymer film, which is spin-coated on a substrate, followed by removal of the stamp. The second step is the pattern transfer, where an anisotropic etching process, such as reactive ion etching (RIE), is used to remove the residual resist in the compressed area. "Reverse" nanoimprint is based on spin coating the polymer on the mould and then transferring it to the substrate similar to conventional NIL. In addition, embedded Mach Zender interferometers and waveguides have been fabricated using the same lithographic techniques while design, fabrication and characterisation issues are discussed.