Moire Polarization Interference Photolithography Based on AZO Molecular Glass Pillar Array for Hierarchical Surface Patterning

A new method termed moire polarization interference photolithography is developed by using a photoresponsive AZO molecular glass (IAC-2) for fabricating hierarchical surface patterns. Arrays of hexagonally arranged submicron-sized pillars are prepared from IAC-2 by soft-lithographic hot embossing. For the interference photolithography, the pillar arrays are sequentially exposed to polarization-type interference fringes formed by the superposition of two laser beams with right-circular polarization and left-circular polarization. By rotating the pillar arrays by a predetermined angle around the surface normal after each exposure, moire patterns are fabricated by deformations of the pillars in response to the local polarization states of the superimposed interference fringes. The fabricated hierarchical surface patterns show features combining the complex mass transfer following the local electric vibration directions of the light wave and the long-range order generated by the moire effect. By increasing the exposure time, patterns with growing complexity are formed through partial merging of the pillars. The material and methodology reported here extend typical interference photolithography from light intensity modulation to a new dimension, including the polarization interference of coherent light. This new approach can provide a powerful platform for the fabrication of various complex surface patterns that are unattainable by conventional methods.