Fabrication of two-dimensional photonic crystals in a chalcogenide glass

Two-dimensional photonic band gap structures consisting of air holes arranged to form a hexagonal lattice were patterned into chalcogenide glass thin films by Focused Ion Beam (FIB) milling. The dimensional parameters for these structures, namely type of lattice, lattice parameter and radius of the holes, were chosen so as to show a photonic band gap relevant to the infrared range, aiming at their subsequent use in the field of chemical sensing and biosensing. The optical behaviour of these structures was determined by calculating the band structure for the TM (magnetic field in-plane) and TE (electric field in-plane) modes. Furthermore, FIB milling was used to fabricate input and output waveguides coupled to the photonic crystals. The transmission spectra of the resulting structures for the TE and TMmodes with two different orientations were also calculated.