A photonic crystal sensor based on the superprism effect

We describe an optical sensing technique, based on the superprism effect in three-dimensional photonic crystals formed by templating colloidal crystals. This method exploits the extreme sensitivity of the diffraction angle to the material properties, such as the refractive index contrast. We outline a theoretical method for analyzing this effect, and apply it to a particular sensing configuration. This sensor should provide an increase by as much as three orders of magnitude in the sensitivity to small changes in index contrast, in comparison with other optical sensing methods.