Abstract:We present a flow-through refractive index sensor for measuring the concentration of glucose solutions based on the application of rectangular glass micro-capillaries, with channel depth of 50 µm and 30 µm. A custom designed and 3D printed polymeric shell protects the tiny capillaries, ensuring an easier handling and interconnection with the macrofluidic path. By illuminating the capillary with broadband radiation centered at λ~1.55 µm, both the transmitted (T) and reflected (R) optical spectrum from the capillary are detected with an optical spectrum analyzer, exploiting an all-fiber setup. Monitoring the spectral shift of the ratio T/R in response to increasing concentration of glucose solutions in water we have obtained sensitivities up to 530.9 nm/RIU and limit of detection in the range of 10 −5 -10RIU. Experimental results are in agreement with the theoretically predicted principle of operation. After the demonstration of amplitude detection at a single wavelength, we finally discuss the impact of the capillary parameters on the sensitivity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.