Fabrication and Optimization of Deep UV Photonic Crystals

We are investigating different synthetic conditions of highly charged silica nanospheres which we use to create photonic crystal wavelength selecting devices. These photonic crystals consist of a crystalline colloidal array of small (30-45 nm diameter) silica nanospheres which are highly monodisperse in size and charge. The current goal is to optimize the size and charge of the particles in order to improve the diffraction properties of our photonic crystals i.e. strong diffraction with a narrow bandwidth. These particles were functionalized with strongly acidic groups, resulting in a high negative surface charge. This high charge leads to electrostatic repulsion between nanospheres and self-assembly into face centered cubic photonic crystals which Bragg diffract a narrow wavelength region of UV light.