Optically isotropic microlens arrays using nanoencapsulated liquid crystals

Abstract

We propose an optically isotropic switchable microlens array (MLA) based on nanoencapsulated liquid crystals (LCs). In its initial state, the encapsulated LC layer has an refractive index intermediate to that of the LC and capsule shell polymer even if the LC molecules' structure has any alignment, because the nanocapsules are much smaller than the wavelengths of the incident visible light. Applying a voltage causes the LC molecules to align vertically within the LC capsules, changing their refractive index from that of the initial state. The MLA can be designed to have switching characteristics by means of index matching between the encapsulated LC layer and the polymer lens structure. The proposed switchable MLA shows high light efficiency and true optical isotropy.