Proposed square spiral microfabrication architecture for large three-dimensional photonic band gap crystals

We present a blueprint for a three-dimensional photonic band gap (PBC) material that is amenable to Large-scale microfabrication on the optical scale using glancing angle deposition methods. The proposed chiral crystal consists of square spiral posts on a tetragonal Lattice. In the case of silicon posts in air (direct structure), the full PBC can be as Large as 15% of the gap center frequency, whereas for air posts in a silicon background (inverted structure) the maximum PEG is 24% of the center frequency. This PBC occurs between the fourth and fifth bands of the photon dispersion relation and is very robust to variations (disorder) in the geometrical parameters df the crystal.