Scalable interference lithography alignment for fabrication of three-dimensional photonic crystals

Holographic lithography is an ideal technique for fabricating three-dimensional photonic crystals. However, a critical stage in the fabrication is the minute alignment of the layers with one another. We present a simple moirelike alignment technique with better than 20-nm translation resolution and 45-murad rotation resolution. This technique can easily be extended to other situations when low-cost, high-precision alignment is needed.