Ultrahigh Sensitivity Refractive Index Sensor Based on Double-Side Polished Photonic Crystal Fiber with Zigzag Gold Film

An ultrahigh sensitivity surface plasmon resonance sensor based on double-side polished photonic crystal fiber is designed, and the gold film with a zigzag cross section is used as the plasmonic material. We study the refractive index sensing characteristics of the proposed sensor by numerical simulation. The results show that compared with the flat gold film structure, the zigzag gold film structure effectively improves the sensing performance, and the sensitivity and resolution of the sensor are significantly enhanced. The maximum wavelength sensitivity and resolution of the proposed sensor can reach 20,000 nm/RIU and 5.00 × 10 −6 RIU, respectively. The working wavelength range of the sensor is between 590 and 1200 nm, and the refractive index range that can be used for detection is 1.350 RIU-1.400 RIU. This can be applied to precise detection of extracellular vesicles, breast cancer cell, and red blood cells. The proposed sensor has significant advantages such as stable structure, ultrahigh sensitivity, fast response, small size, and saving noble metal. It has great application potential in biomedical testing and medical equipment.