Published in : Applied Optics

Abstract : A modified solid-core Photonic Crystal Fiber (PCF) based plasmonic sensor is proposed where light propagation through the PCF is controlled by scaling down of air-holes. The modified core facilitates to easy excitation of plasmonic surface resulting improve the senor performance. The chemically stable gold is externally coated on the PCF surface which helps to establish surface plasmon resonance (SPR) phenomena. The response of the sensor is analyzed based on the numerical method and the design parameters are optimized to enhance the sensing performance. The asymmetric structure of fiber-core provides the polarization controllability, and significantly suppress the y-polarized response to achieve a dominant x-polarized response and additional functionalities. The sensor exhibits the maximum wavelength sensitivity of 11,000 nm/RIU (refractive index unit) and sensing resolution of 9.09×10-6 RIU in the x-polarized mode. Also, the sensor exhibits maximum amplitude sensitivity of 631 RIU-1 and a good figure of merit (FOM) is 157 RIU-1. Furthermore, the sensor can detect the unknown analytes refractive index (RI) in the sensing analyte RI range of 1.33 to 1.40 which will lead to finding the potential applications in biomolecules, organic chemicals and environment monitoring.

DOI : 10.1364/AO.400301