Optical Interference Lithography Using Azobenzene-Functionalized Polymers for Micro- and Nanopatterning of Silicon Light-induced mass transport in azobenzene-functionalized polymers is exploited in optical interference lithography to fabricate large-area, periodic 1D and 2D silicon nanostructures. The demonstrated technique is a fast, reliable, and cost-effective alternative to conventional photoresist-based methods of nano- and microfabrication. Potential applications of the technique range from optics and photonics to functional materials and coatings.