D-type photonic crystal fiber refractive index sensor based on Bloch surface waves

Abstract

Bioassays are important in health assessment, disease diagnosis, treatment monitoring, disease prevention, and environmental monitoring to provide better health management and quality of life for individuals and society. A D-type photonic crystal fiber optic sensor based on Bloch surface waves is proposed for biological detection within an ultra-wide refractive index. The designed D-type fiber was side-polished and alternately deposited with one-dimensional photonic crystals (1DPCs) on the polished side, consisting of a set of TiO2 and SiO2 alternating media with moderate refractive index differences. The designed PCF consists of symmetric air holes and polished structures. The structural parameters of this sensor are also analyzed and discussed in order to obtain better detection performance. The designed Bloch surface wave D-type photonic crystal fiber optic sensor has a maximum refractive index sensitivity of 5400 nm/RIU and a maximum amplitude sensitivity of 513.00RIU−1. The sensor also has a resolution of 1.85×10−5RIU and an excellent maximum quality factor (FOM) of 222.43RIU−1. These results show a higher figure of merit (FOM) than conventional methods, resulting in increased sensitivity and accuracy. The proposed sensor can detect the RI of unspecified analytes between 1.20 and 1.50, allowing for the analysis of many different types of analytes, such as viruses, blood plasma, cancer cells, sugars, proteins, DNA/RNA, and many more.