Sol-gel-derived micron scale optical fibers for chemical sensing

We report for the first time on the preparation of organically-doped room temperature processed sol-gel-derived micron scale optical fibers as platforms for chemical- and bio-sensors. Micron scale optical fibers are drawn from fluorescent dye-doped tetraethoxysilane (TEOS)-derived sol-gel solution processed under ambient conditions. Such a simple methodology to entrap organic and even bioactive species within the optical fiber offers many advantages over more conventional ways of immobilizing organic probes for the development of optical sensors. Specifically, we report on the photophysical properties of fluorescein (a pH sensitive fluorescent dye) and rhodamine 6G (R6G; laser dye) entrapped within sol-gel-derived optical fibers. We present the preliminary results on the viability of such doped optical fibers for chemical sensing. Our results demonstrate that a fluorescein-doped sol-gel-derived optical fiber responds to ammonia and acid vapors with a response time of 1-2 seconds.