Optical Sensor Waveguide Refractive Index Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical sensors face challenges in detecting local changes in refractive index of dielectric media with low sensitivity, particularly when measuring the total intensity reflected by the active region, which makes it difficult to accurately determine refractive index changes.
Innovation Solution
The method involves emitting a light beam to propagate through a waveguide with at least two propagation modes, measuring the spatial distribution of intensity reflected or transmitted by the active region, and using a database to link the intensity distribution with refractive index changes relative to a reference medium, allowing for the detection and determination of local refractive index changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the total intensity reflected by the active region is measured, then the measurement process is simple, but the sensitivity of the sensor is low
Solution Approach 1:
The patent divides the measurement approach by separating the analysis of different propagation modes. Instead of measuring total intensity as a single value, the method segments the light into multiple propagation modes (at least N≥2 modes) and measures their individual intensities or spatial distributions, thereby increasing sensitivity while maintaining operational feasibility through systematic measurement procedures
Solution Approach 2:
The patent transitions from measuring a single scalar value (total intensity) to measuring spatial distribution patterns across multiple dimensions. By analyzing the spatial distribution of intensity for at least one zone and utilizing multiple propagation modes, the method adds dimensional information that significantly enhances sensitivity to refractive index changes
2Measurement precision
If multiple propagation modes are used, then the sensitivity is enhanced, but the complexity of the measurement system increases
Solution Approach 1:
The patent employs self-service principles by utilizing the waveguide's inherent ability to support multiple propagation modes. The system leverages the natural modal structure of the waveguide without requiring external mode-selective components, allowing the waveguide itself to provide the multi-mode functionality needed for enhanced sensitivity
Solution Approach 2:
The patent changes the measurement parameter from total intensity to spatial distribution patterns of multiple propagation modes. By monitoring how the spatial distribution changes with refractive index variations, the system achieves enhanced sensitivity while managing complexity through parameter transformation rather than structural complexity
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
This approach significantly enhances the sensitivity of the sensor by up to 25 times, enabling precise detection of refractive index changes through localized intensity measurements, improving the accuracy of analyte detection and refractive index determination.
Implementation Method 1
emitting a light beam at the input of the waveguide so that this light beam can be propagated, within the waveguide, according to at least N propagation modes
Implementation Method 2
The interaction between certain propagation modes of the light beam and the metallic layer makes it possible to generate a plasmon resonance at the interface between the metallic layer and the dielectric medium
Implementation Method 3
measuring the intensity of at least one zone of the spatial distribution of the intensity of the light beam reflected or transmitted by said active region
Implementation Method 4
detecting the local change in the refractive index of the dielectric medium
Data Source
AI summary
The invention relates to a method for detecting a local change in refractive index of a dielectric medium located on the surface of an optical sensor, said optical sensor comprising for this purpose a waveguide comprising a region, called the active region, covered with at least one metallic layer in contact with the dielectric medium, said method comprising the following steps:a) emitting a light beam at the input of the waveguide so that this light beam can be propagated, within the waveguide, according to at least N propagation modes, where N is a natural integer such that N≥2;b) measuring the intensity of at least one zone of the spatial distribution of the intensity of the light beam reflected by said active region of the optical sensor; andc) detecting the local change in the refractive index of the dielectric medium by means of a database supplying the link between the intensity of said at least one zone of the spatial distribution of the intensity of the light beam reflected by the active region of the optical sensor and a change in refractive index of a reference medium.