Photonic crystal all-polymer slab resonators

Moderate air-hole-fraction photonic crystal square lattice structures defining small cavity resonators were created by etching air holes of 0.15μm radius to a depth of 3μm in an all-polymer slab waveguide. Transmission measurements with subnanometer resolution resolved the complete transmission spectra and highly resonant defect peaks with quality factors Q larger than 400. Simulations demonstrate the importance of high-aspect-ratio etching depths for maintaining vertical index-confinement and vertically quasisymmetric field distributions despite the material index asymmetry. Experimental spectra are shown to match the three-dimensional finite-integration simulations. Enhanced quality factors of up to 20000 were found in the simulations for cavities bounded by modified radius air holes. In this manner resonators with very low out-of-cavity losses and high defect state transmission may be created in moderate index contrast polymer waveguide slabs.