Optically active inverse opal photonic crystals.

Chiral photonic crystals have been a widely investigated topic in chemistry, physics and biology. Till now, the researches about chiral photonic crystals are conducted on the objects of helical structures, while the chiral photonic crystals made of periodic chiral media remain unexplored experimentally. In this work, we have successfully constructed three-dimensional chiral polymer inverse opal photonic crystals (3D CPIOPCs) by a template-based method. Impressively, the 3D CPIOPCs exhibit emerging circular dichroism responses near the photonic band gaps. The experiments and calculations clearly elucidate the contribution of photonic structures and chiral media to this characteristic optical activity.