Low-refraction-index PCF-SPR (photonic crystal fiber-surface plasmon resonance) sensor working at middle infrared band

Abstract

The invention relates to an optical fiber sensor, in particular to a low-refraction-index PCF-SPR (photonic crystal fiber-surface plasmon resonance) sensor working at a middle infrared band. Inner layer air holes, outer layer air holes and two symmetrically distributed round passages of liquid to be tested are arranged in a cladding layer of optical fiber; a gold film is plated on the inner wall of the round passage of liquid to be tested; a tiny opening is formed in the outer side of the round passage of liquid to be tested; the inner layer air holes and the outer layer air holes are in regular hexagon staggered arrangement; the radius of the outer layer air hole is greater than the radius of the inner layer air hole; the optical fiber is made of silicon dioxide; the optical fiber is refraction index guide type photonic crystal fiber. The resonance wavelength is at the middle infrared band; the low-refraction-index liquid to be tested can be detected; particulates in a solution to be tested can be selectively filtered; the size is small; the microminiaturization of the sensor is easily realized; the average spectrum sensitivity reaches up to 8850 nm/RIU. The sensor is mainly used for detecting the refraction index of the solution to be tested and performing selective detection analysis on chemical substances in the solution.

Description

[0001] Technical field: [0002] The invention relates to an optical fiber sensor, in particular to a low-refractive-index PCF-SPR sensor working in the mid-infrared band. [0003] Background technique: [0004] Surface plasmon resonance (SPR) sensing technology is a rapidly developing optical sensing technology. In addition to the general characteristics of optical sensors, surface plasmon resonance sensors also have outstanding features such as high sensitivity, no labeling, and real-time detection. They have broad prospects in the fields of biology, drug development, medical diagnosis, energy, and environmental pollution. Optical fiber sensors have a wide range of applications, not only small in size, light in weight, easy to form a network, but also anti-electromagnetic interference, anti-corrosion, high sensitivity, and bendable optical path. However, traditional fiber optic sensors still have many disadvantages that are difficult to solve, such as poor polarization maint...

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Problems solved by technology

However, most of the previously proposed PCF-SPR sensors work in the range of visible light or near-infrared light, and the measured

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