Filtering light with nanoparticles: A review of optically selective particles and applications

The ability to selectively and controllably interact with light is useful to a wide range of devices. With the advent of nanotechnology, we now have the ability to create optical materials, which are designed from the bottom up, with dimensions of the order of the wavelength of light. While it has been known for some time that nanoparticles exhibit such exciting properties, recent (widespread) research in nanoparticles has significantly increased our understanding of how to fabricate and use nanoparticles for a myriad of enduring and emerging optical applications. Drastic modifications to the “bulk” optical properties of standard materials in these applications are possible, enabling “nanoengineered” optical properties with several degrees of design freedom, including material, size, morphology, surrounding media, and nearby structures. Understanding these sensitivities has led to optical control from the ultraviolet through the infrared spectrum. To highlight this, the following review provides a comprehensive snapshot of how these effects have been captured in models and experimentally demonstrated in terms of spectral selectivity in absorption, scattering, and emission. In addition, we discuss recent progress toward using nanoparticles in real applications, most commonly in fluid suspensions or solid thin films as a means to create the next generation of highly scalable and (potentially) low-cost spectrally selective optical materials.