Pixelated Photonic Crystals

Photonic crystals can prevent or allow light of certain frequencies to propagate in distinct directions in anomalous and useful ways for use as waveguides, laser cavities, and topological light propagation. However, there exist limited approaches for fundamental reconfiguration of photonic crystals, such as changing the unit cell to various and on-demand geometries and symmetries. This work introduces the concept of pixelated 2D photonic crystals where the variability of the dielectric profile is achieved by a pixelated matrix of the material. Specifically, the cross sections of dielectric cylindrical pillars distributed in a photonic crystal lattice are replaced with pixelated circles using different resolutions and the corresponding band diagrams are calculated. The comparison to the band diagrams of the original structure shows that the original-and today typically used-cylindrical design can be well approximated by as few as 5x5$5 \times 5$ square switchable pixels while retaining less than 1%$$ change in the photonic band structure. Experimental realization of switchable pixelation is proposed based on the liquid crystal display (LCD) technology with high birefringence materials. More generally, the demonstrated approach to reconfigurable 2D photonic crystal based on switchable pixels can enable realization of diverse fundamentally reconfigurable advanced optical materials.

Automated summary

Photonic crystals can control the propagation of light in unique ways, and this work introduces the concept of pixelated 2D photonic crystals to enable reconfigurable optical materials. By replacing the cross sections of cylindrical pillars with pixelated circles, as few as 5x5 switchable pixels can approximate the original cylindrical design while maintaining the photonic band structure. The proposed experimental realization is based on liquid crystal display technology.