Optical materials and metamaterials from nanostructured soft matter

Soft materials such as block copolymers, liquid crystals and colloidal assemblies are excellent candidates for use in optical applications due to their ability to spontaneously self-assemble into ordered structures on optically-relevant length scales. Some of these applications rely on optical properties that are intrinsic to the structure and chemical composition of the soft material itself, while others are reliant on the presence of inorganic nanomaterials within the soft material to produce the properties of interest. However, soft materials can be used to generate optical phenomena that originate not just from the intrinsic properties of the nanomaterials, but from their spatial organization as well. In the latter case, exotic optical phenomena such as light focusing beyond the diffraction limit, negative index of refraction and nonlinear photonics appear. These properties originate from the collective response of multiple nanostructures organized to produce an ordered metamaterial. Soft materials, being an excellent medium to convey order on the nanoscale, can be utilized in next generation optical applications to create this kind of organization. Here, we survey how soft matter can be leveraged in optical applications by exploiting self-assembly and directed self-assembly as methods to produce ordered structures with desirable properties. We highlight applications where the soft material is the optically active component, and others where it's used in tandem with nanomaterials. Specifically, we focus on how soft materials can be used to spatially organize inorganic nanomaterials for use in optical applications where the controlled assembly of such nanomaterials is crucial.