Optofluidic Refractive Index Sensor Based on Partial Reflection

We demonstrate a novel optofluidic refractive index （RI） sensor with high sensitivity and wide dynamic range based on partial reflection. Benefited from the divergent incident light and the output fibers with different tilting angles, we have achieved highly sensitive RI sensing in a wide range from 1.33 to 1.37. To investigate the effectiveness of this sensor, we perform a measurement of RI with a resolution of ca. 5.0× 10^-5 refractive index unit （RIU） for ethylene glycol solutions. Also, we have measured a series of liquid solutions by using different output fibers, achieving a resolution of ca. 0.52mg/mL for cane surge. The optofluidic RI sensor takes advantage of the high sensitivity, wide dynamic range, small footprint, and low sample consumption, as well as the efficient fluidic sample delivery, making it useful for applications in the food industry.