Optical Differential Interrogation for SPR Imaging
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Solution Overview
Problem
Conventional SPR sensing technologies face limitations in measuring a large number of samples simultaneously due to narrow dynamic range, high noise sensitivity, and increased data throughput, particularly in methods like phase detecting and angle interrogation.
Innovation Solution
An optical differential interrogation method that involves incidenting first and second wavelength light on a sample while varying the incident angle, detecting the intensity of reflection light from both, and identifying the sample based on the difference or sum of these intensities to achieve improved dynamic range and reduced noise robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the angle interrogation method is used to provide good resolution with wide dynamic range, then measurement precision is improved, but data throughput increases due to finer angle scanning requirements
Solution Approach 1:
The patent changes the interrogation parameter from angle scanning to wavelength scanning. By using a tunable laser that scans through wavelengths rather than scanning angles, the system achieves the same resolution and dynamic range without requiring fine angular steps, thus reducing data throughput while maintaining measurement precision
Solution Approach 2:
The patent replaces the mechanical angle scanning system with an optical wavelength scanning system using a tunable laser. This substitution eliminates the need for mechanical angle adjustment and fine scanning, reducing the data throughput burden while preserving the ability to measure with high resolution across wide dynamic ranges
2Ease of operation
If the reflection intensity measurement method is used for easy image measurement, then ease of operation is improved, but resolution deteriorates to about 10 RIU to 5 RIU
Solution Approach 1:
The patent changes the measurement approach by using wavelength scanning instead of fixed-angle reflection intensity measurement. This allows the system to maintain ease of operation while achieving superior resolution by measuring the wavelength shift caused by SPR, rather than relying on intensity changes that are susceptible to noise and limited dynamic range
3Measurement precision
If the phase detecting method is used to provide best resolution, then measurement precision is improved, but device complexity increases due to narrow dynamic range and complex optical system configuration
Solution Approach 1:
The patent adopts wavelength scanning as the interrogation method, which provides a balanced approach between resolution and system complexity. By measuring wavelength shifts rather than phase changes or intensity variations, the system achieves high resolution without requiring the complex optical configurations needed for phase detection, while also providing wider dynamic range
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 method enhances angular resolution and reduces data throughput, enabling more efficient measurement of multiple samples with improved noise resistance and wider dynamic range compared to conventional methods.
Implementation Method 1
Surface plasmon resonance (SPR) is a phenomenon in which, when a light-induced electromagnetic field is applied to an interface between a metal and a dielectric, a surface charge is induced on the interface due to discontinuity of the interface between the two media, and incoherent vibration occurs in an excited state in which the induced surface charges are collectively excited.
Implementation Method 2
When P-polarized (or TM-polarized) light is incident on an interface between a metal and a dielectric media, an incident wave and an oscillating wave of a surface plasmon match each other in phase at a specific angle above a threshold angle at which total reflection occurs, and thus energy of light incident on the interface is absorbed
Data Source
AI summary
According to the present invention, an optical differential interrogation method for surface plasmon resonance imaging including: letting first incident light of a first wavelength and second incident light of a second wavelength to be incident on a sample while varying an incident angle; detecting intensity of first reflection light of the first incident light and intensity of second reflection light of the second incident light; and identifying the sample by using a difference between the intensity of the first reflection light and the intensity of the second reflection light, can be provided, and thus it is possible to obtain much better angular resolution while using a detector or a camera, which has a relative low receiving sensitivity and a sensor chip where samples having various characteristics are two-dimensionally arrayed and integrated can be effectively measured.