Highly amplitude-sensitive photoniccrystal-fiber-based plasmonic sensor

Simple structure, quick response, and highly sensitive miniaturized sensors are highly desirable for the broadrange of sensing applications. In this work, we numerically investigated a highly sensitive photonic-crystalfiber (PCF)-based plasmonic sensor for refractive index sensing. We consider gold as the plasmonic material,which is used outside the fiber structure to exhibit the plasmonic phenomena and to help detect the surroundingmedium refractive index. The proposed PCF is designed to enable the evanescent field to interact with an externalsensing medium leading to a highly sensitive response. The sensor performance has been investigated by wavelength and amplitude interrogation methods. The proposed sensor exhibits the maximum amplitude sensitivity of2,843 RIU-1 with the sensor resolution of 3.5 × 10-6 RIU, which is the highest among the reported PCF SPRsensors, to the best of our knowledge. It also shows wavelength sensitivity of 18,000 nm/RIU and sensor resolution of 5.6 × 10-6 RIU. The figure of merit of the proposed sensor is about 400. The sensor response alsoallows us to detect the refractive index variation in the range of 1.33 to 1.41. Such promising results and broadsensing range ensure that the proposed sensor will be a suitable candidate for biological analytes and biochemicaland organic chemical detections.