Surface plasmon resonance sensor based on coreless fiber for high sensitivity

A compact and simple surface plasmon resonance sensor based on coreless fiber for refractive index measurement is developed. Compared with common SPR sensors, the proposed SPR sensor has a shorter length of 1 cm, avoids a taper and can be used to detect a wider range of 1.335–1.4019. The resonant wavelength shifts ∼200 nm to the longer wavelength in the refractive index range of 1.3335–1.4019. The average refractive sensitivity of 2836 nm/RIU is obtained in the range of 1.3335–1.4019, and the highest sensitivity can reach 4328.2 nm/RIU. Furthermore, our device has the advantages of small size, wide measuring range, excellent stability and short response time, which is appropriate for biological sensing.