Controlling the mode profile of photonic crystal nanobeam cavities with mix-and-match unit cells

We report simulations and experimental measurement of a photonic crystal (PhC) designed with different unit cell geometries in a single device. This mix-and-match approach enables enhanced mode manipulation by incorporating non-traditional unit cell shapes into a one-dimensional PhC nanobeam cavity. Inclusion of a bowtie-shaped unit cell in the center of a mix-and-match PhC nanobeam cavity comprised elsewhere of either circular or antislot unit cells leads to a 2 order of magnitude reduction in the mode volume of the cavity while maintaining a similar quality factor. (C) 2020 Optical Society of America