High reflectivity Bragg reflectors based on a gold nanoparticle/Teflon-like composite material as a new approach to organic solvent detection

We report on the properties of a new optical sensing element for organic solvents based on polymeric distributed Bragg reflector (DBR), which can be easily interfaced with optical fibers. The DBR is a periodic stack of alternating Teflon-like and gold nanoparticle/Teflon-like composite layers showing high reflectivity in the optical telecommunication spectral range and sensing properties due to the peculiar absorbing properties of the composite layers. The swelling of the composite layers in presence of organic vapors causes a DBR periodicity change and this results in the shift of the high reflectivity window.