A focused ion beam (FIB) is used to process 2-D self-assembled photonic porphyrin film flats to fabricate couplers in 2-D porphyrin slabs. These self-assembled structures have an initial root mean squared (rms) values for surface roughness < 0.5 nm as measured by atomic force microscopy. Under appropriate FIB processing and cutting conditions, the rms value for surface roughness falls to < 0.4 nm.