Interferometric lithography provides a simple, inexpensive technique for the fabrication of large areas of extreme sub-micrometers structures. Using a 364 nm Ar-ion laser source, gratings with periods to 0.2 micrometers and CDs as small as 30 nm are reported. Multiple exposure interferometric lithography provides the all important extension to 2-D structures. Importantly, pairwise exposures maintain the effectively infinite depth-of-field while still allowing complex structures. Mix and match with conventional optical lithography provides additional flexibility. An interdigitated structure suitable for high-speed photodetectors and conductive particle sensors is an example.