Influence of polarization combinations on compound photonic crystals based on single-step holographic interferometry

Compound photonic crystals (CPCs), composed of two or more nested simple photonic crystal lattices, have attracted considerable attention owing to their unique optical properties; however, controlled fabrication of special unitcell geometries remains challenging. In this work, based on multi-beam interference theory, we present a single-step holographic interferometry for fabricating CPCs. This method possesses notable advantages including large-area, low cost, high efficiency, and rich patterns. A four-beam configuration with specific symmetry is employed here and numerical calculations are carried out to simulate holographic fabrication of CPCs. The influence of beam polarizations on unitcell geometry and interference contrast is systematically investigated by simultaneously adjusting the polarization of single-, dual-, triple-, or quadruple-beam combinations. The resulting interference fields reveals that diverse special unitcell geometries of CPCs, such as double-stick, tooth-shaped, Y-shaped, and plano-convex-lens patterns, are achieved. These findings provide theoretical guidance and key polarization control for the fabrication of CPCs with specific unitcell shapes.