Distributed liquid refractive index sensing device based on optical fiber surface plasma resonance

Abstract

The invention provides a distributed liquid refractive index sensing device based on optical fiber surface plasma resonance. Two SPR sensing regions plated with nanometer metal films with different thicknesses are processed on a plastic-wrapped optical fiber, light emitted by a light source enters the plastic-wrapped optical fiber through a single-mode optical fiber, SPR is stimulated on the interface of the nanometer metal film in the first SPR sensing region and liquid with the refractive index to be detected and the interface of the nanometer metal film in the second SPR sensing region and the liquid with the refractive index to be detected, light intensity is attenuated at the corresponding resonance wavelength part, SPR is generated at the small wavelength part by the nanometer metal film with the small thickness, and SPR is generated at the large wavelength part of the nanometer metal film with the large thickness; finally, sensing spectra are analyzed with a spectrograph, and then the refractive index of the liquid is obtained through extrapolation. The distributed liquid refractive index sensing device has the outstanding advantages of being simple in structure, convenient to manufacture, high in sensitivity, capable of achieving distributed sensing and the like, and has huge application potential in the fields such as biosensing, pharmaceutical research and development, food safety, environment monitoring and medical diagnosis.

Description

technical field [0001] The invention relates to an optical fiber sensing device, in particular to a high-sensitivity distributed liquid refractive index sensing device based on optical fiber SPR. Background technique [0002] Refractive index is one of the important optical parameters of substances. With the help of refractive index, the optical properties, purity, concentration and dispersion properties of substances can be understood. At the same time, in chemical industry, medicine, food, petroleum and other industrial departments and college experiments, some The refractive index and concentration of the liquid. Therefore, accurate measurement of the refractive index of liquid is of great significance in many research fields. [0003] Optical fiber surface plasmon resonance (Surface Plasmon Resonance, SPR) is a physical phenomenon produced by the interaction between the dielectric layer at the bare core and the external medium to be measured during the propagation of th...

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Problems solved by technology

In the above scheme, a certain thickness of gold film needs to be plated on the sensing area. On this basis, three consecutive sub-sensing areas are plated with different thicknesses of Ta 2 o 5 The thin film is used as a modulation layer, becaus...

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