Near-infrared series PCF-SPR sensor for low refractive index detection

Abstract

The invention relates to an optical fiber sensor, in particular to a near-infrared series PCF-SPR sensor for low refractive index detection. The photonic crystal fiber comprises two eccentric photoniccrystal fibers which are in series contact and are symmetrically distributed, three layers of air holes arranged in a regular hexagon shape are formed in the cladding outside the air holes in the centers of the optical fibers, fiber cores are arranged at the positions of the air holes in the second layer on the X axis, the fiber cores of the two optical fibers are opposite at a short distance, and the vertex of the hexagon on the outermost layer is a small air hole with the hole diameter smaller than that of the air holes; the arrayed air holes are air holes arrayed in a hexagonal shape and six small air holes are formed in the outer layer; an upper gold wire and a lower gold wire are arranged between the outer walls of the optical fibers and are in contact with the outer walls of the optical fibers; an annular to-be-detected analyte channel is formed in the outer side of the optical fiber. The sensor is simple in manufacturing process, can be massively produced and is easy to realize; the structural size is small, and miniaturization is easy to achieve; and due to the core shift structure, the evanescent field can easily penetrate through the gold wire, so that higher sensitivityis realized under the action of the evanescent field and the outside.

Description

Technical field: [0001] The invention relates to an optical fiber sensor, in particular to a near-infrared series PCF-SPR sensor for low refractive index detection. Background technique: [0002] Surface Plasmon Resonance (SPR) technology plays an important role in the field of sensing. With its outstanding advantages such as real-time analysis, no labeling, and high sensitivity, it is widely used in life sciences, medical diagnosis, environmental monitoring, drug screening, and food safety. and other fields. The emergence of photonic crystal fiber (Photonic Crystal Fiber, PCF) has once again pushed the fiber sensor based on surface plasmon resonance technology to a new research hotspot. Photonic crystal fiber is composed of periodically arranged air holes, and different air holes are designed to contain corresponding transmission modes. Compared with traditional fiber optic sensors, photonic crystal fiber optic sensors have a flexible structure and high sensitivity, and h...

AI Technical Summary

Problems solved by technology

For PCF-SPR sensors, the uniformity of the material that excites the surface plasmon resonance on the optical fiber and the difficulty of the coating process are very critical. Due to the miniaturization and circular structure of the optical fiber, the achievable accuracy of this process is not high. It is determined that although the emergence of D-shaped optical fibers provides a coating platform for corresponding materials, the production of D-shaped optical fibers is not easy.

In addition, the current research on PCF-SPR sensors mainly focuses on the detection of high refractive index liquid environments in the visible light band, and the range of refractive index detection is limited.

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