Fabrication and Chemical Modifications of Photonic Crystals Produced by Multiphoton Lithography

Nanoscale features as small as 65 ± 5 nm have been formed reproducibly by using 520nm femtosecond pulsed excitation of a 4,4'-bis(di-n-butylamino)biphenyl chromophore toinitiate crosslinking in a triacrylate blend. Dosimetry studies of the photoinducedpolymerization were performed on chromophores with sizable two-photon absorptioncross-sections at 520 and 730 nm. These studies show that sub-diffraction limited linewidths are obtained in both cases with the lines written at 520 nm being smaller. Three-dimensional multiphoton lithography at 520 nm has been used to fabricate polymericwoodpile photonic crystal structures that show stop bands in the near-infrared spectralregion.