Refractive Index Sensor Using Nanoparticle-Coated Waveguide
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Solution Overview
Problem
Existing refractive index sensors have low resolution, requiring complex light sources and spectrometers to determine wavelength shifts, making them inefficient and inaccurate.
Innovation Solution
A waveguide device with a core and cladding, featuring a fiber Bragg grating and nanoparticles, where the cladding is partially removed to increase intensity losses based on the refractive index, allowing for more accurate intensity measurements with simpler equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fiber Bragg grating sensor is used to measure refractive index by wavelength shift, then the measurement can be performed, but the resolution is low and complex light sources and spectrometers are required
Solution Approach 1:
The patent changes the measurement parameter from wavelength shift to intensity loss. By removing the cladding and coating the core surface with nanoparticles, the sensor measures intensity changes of the guided light mode instead of wavelength shifts, which provides higher resolution and allows the use of simpler light sources and detectors
Solution Approach 2:
The cladding layer is extracted (removed) from the waveguide structure in the measurement region. This extraction allows the evanescent field to interact directly with the nanoparticles coated on the core surface, enabling the intensity-based measurement mechanism that resolves the contradiction between precision and device complexity
2Measurement precision
If the cladding is partially removed and nanoparticles are applied to increase intensity losses, then measurement accuracy is improved, but the device structure becomes more complex
Solution Approach 1:
The cladding removal and nanoparticle coating are applied locally only in the measurement region, not along the entire waveguide length. This local modification approach improves measurement accuracy while minimizing the increase in overall device complexity and maintaining the simplicity of the waveguide structure in non-measurement regions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device achieves significantly clearer measurement signals with increased accuracy and reduced operational effort, enabling precise refractive index determination and detection of pressure fluctuations.
Implementation Method 1
a second longitudinal section 22 in which a Bragg grating 4 is located, which causes a wavelength or wavelength range predeterminable by the grating constant to be reflected
Implementation Method 2
The sensor can be immersed in gases or liquids, whereby the Bragg wavelength reflected by the Bragg grating changes depending on the refractive index or refractive index of the medium surrounding the sensor
Implementation Method 3
at least a partial area of the surface 210 in the first longitudinal section 21 with nanoparticles 3. This feature has the effect of causing intensity losses of the wave reflected by the Bragg grating. These losses depend on the refractive index of the medium surrounding the first longitudinal section
Data Source
Figure 1~2
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AI summary
The invention relates to a device for determining a refractive index or a hydrophone, which contains at least one waveguide (10) with a core (11) and cladding (12) surrounding the core (11), wherein the cladding (12) is at least partly removed in at least one first longitudinal portion (21) and the core contains at least one fiber Bragg grating (4) in at least one second longitudinal portion (22), wherein at least one part of the surface (210) in the first longitudinal portion (21) is provided with nanoparticles (3) and the device furthermore contains an apparatus for detecting the intensity of the light reflected or transmitted by the fiber Bragg grating (4). Furthermore, the invention relates to a method for producing and using this device.