Modeling and test of fiber-optics fast SPR sensor for biological investigation

Surface plasmon resonance (SPR) sensors are high sensitive optical system often used for investigations on organic samples or in general for other fundamental research topics. Normally a SPR sensor is based on a prism on which a thin layer of gold has been deposited. These sensors are usually full-size optical devices, heavy and difficult to transport. In the effort to miniaturize and make more flexible and light SPR sensors we developed a novel system based on a metal-coated optical fiber. Its optical and sensing characteristics were studied using an analytical approach and with the aid of a numerical Monte Carlo method. We will describe the fabrication of an actual sensor and the development of an experimental setup realized for sensing tests. We experimentally demonstrated the ability of the optical fiber sensor to detect the presence of a 2 nm octadecane thiol organic film; measurements showed good S/N ratio and rapid response of few seconds time. As far as we know, our system is the fastest SPR sensor realized so far.