Lab-on-fiber technology for advanced plasmonic nano-optrodes

Optical fibers technology has experienced a tremendous growth and advancement over the past several decades, not only in transmission systems for communications (where nowadays totally dominate especially at the high performances level) but also in the sensing field. For this reason, there is an ever increasing need to add new functionalities and improve the performances, through the integration on the optical fibers of advanced functional materials providing the control and manipulation of light at nanoscale. Both metallic and dielectric nanostructures (in particular photonic and plasmonic crystals) seem to meet that need since they offer unprecedented opportunities for sub-wavelength field confinement and resonant field enhancement. Many prestigious research groups in the photonic community are thus focusing their efforts to fuse together the world of nanotechnologies with optical fibers, leading to the development of a novel and intriguing technology known as “Lab on Fiber”. The integration of nanostructures within optical fibers is giving rise to a new generation of highly functionalized all in-fiber nanoprobes which, being easily and remotely connectable to complex illumination systems and demodulation units, may partially overcome the issue related to the extreme integration of all the components required at lab-on-chip level. In order to address the fabrication issues and adapt modern nanotechnologies facilities to properly work on unconventional substrates such as the case of optical fibers, different strategies and processes have been recently proposed. Among them, our multidiscilinary research group has demonstrated a reliable fabrication path which allows to integrate onto the tip of a standard single mode optical fiber both metallic and dielectric materials patterned at micro and nano-scale by means of a direct writing approach.