Mechano-optical octave-tunable elastic colloidal crystals made from core-shell polymer beads with self-assembly techniques

Elastic colloidal crystals, even without a full photonic band gap, hold promise for fascinating applications and for easy large-scale fabrication by self-assembly. However, high mechanical robustness is required for optical, decorative, or security applications, such as tunable optical modulators/filters or optical tension indicators. Here, we present brilliantly colored filled-pore colloidal crystals that withstand elongation by 100%, i.e., one optical octave. We employ a variety of vertical deposition techniques to self-assemble monodisperse core-shell polymer beads with a film-forming shell and flexible core. We find a good theoretical description of crystal thickness for all techniques. The crystals have centimeter-sized macroscopic order, and their orientation is fully controlled by the substrate plane and meniscus line.