Realization of Structural Color by Direct Laser Write Technique in Photoresist

We report realization of structural color in 3D woodpile photonic crystal structures fabricated by femtosecond direct laser write (DLW) lithography in photoresist. The structural color in the fabricated samples was obtained due to spectral regions with high optical reflectivity associated with higher photonic bands well above the fundamental (lowest frequency) photonic stop gap, which allowed realization of visible colors without the need to reduce the lattice period. This advantage facilitates easier and faster DLW fabrication, and can be exploited for realization of structural color materials for various applications, for example optical environmental sensing.