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...

AI Technical Summary

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 refractive index of the liquid to be tested is generally above 1.3, which are two difficulties that need to be overcome in this field.

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