Nanoimprinted passive optical devices

We report on the feasibility and process parameters of nanoimprint lithography to fabricate low refractive index passive optical devices. Diffraction gratings printed in polymethylmethacrylate (PMMA) exhibit a sharp dispersion with a full width at half maximum of about 20 nm. Waveguides were printed in polystyrene (PS) on silicon oxide and had losses between 8-20 dB cm-1 at wavelengths between 650-400 nm, respectively. Finally, one-dimensional photonic structures were also printed in PS and their transmission and morphology characterized. The expected Bragg peak was observed in transmission and atomic force microscopy images have shown a good pattern transfer. A square lattice was printed in PMMA and more than 40 print cycles were obtained, i.e., potentially more than 1000 imprints from one master stamp.