Sol-gel-derived photonic structures: fabrication, assessment, and application

Sol-gel is a handy, very flexible, and cheap method to fabricate, study, and apply innovative photonic structures. The possibility of starting from molecular precursors and elementary building blocks permits to tailor structures at the molecular level and to create new materials with enhanced performances. Of specific interest for the study of important physical effects as well as for application in light management are confined structures on the nano-micro scale as photonic crystal and planar waveguides. Activation by luminescent species and in particular by rare earth ions allows results in the integrated optics area covering application in sensing, biomedical diagnostic, telecommunication, lightning, and photon management. The present review is focused on some recent results obtained by the authors in Sol-gel photonics. The first part presents colloidal structures including single nano-micro spheres and photonic crystal structures. The second part of the review deals with amorphous and transparent glass-ceramic employed for the fabrication of confined structures in planar format. Some specific application are also reported to highlight the role of sol gel photonics in the development of high performance optical sensors, waveguide lasers, and nanostructured materials.