SPR Sensor Differential Phase Interrogation
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Solution Overview
Problem
Current surface plasmon resonance (SPR) phase detection systems are sensitive to mechanical vibrations and phase errors, limiting their stability and application, especially in noisy environments, and lack the capability to record phase distribution over the sensing surface, which is crucial for bio-reaction monitoring and simultaneous analysis of multiple analytes.
Innovation Solution
An optical sensing device that enhances phase shift by allowing the incident beam to pass through the sensing surface at least twice, using a beam splitter to divide the light into two beams, with one beam reflected by a metal-coated 60° equilateral SF18 glass prism sensing surface, and a detecting mechanism that converts the beams into a two-dimensional interference fringe pattern, allowing for differential phase measurement between p- and s-polarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase detection is used to improve sensitivity, then measurement precision is improved, but stability deteriorates due to sensitivity to mechanical vibrations and phase errors
Solution Approach 1:
The patent introduces a reference optical path as an intermediary element that does not interact with the analyte but experiences the same environmental disturbances. This reference path serves as a mediator to cancel out common-mode noise through differential measurement, allowing phase detection to maintain high sensitivity while achieving stability by subtracting the reference signal from the sensing signal
Solution Approach 2:
The patent changes the measurement parameter from absolute phase detection to differential phase detection. By measuring the phase difference between the sensing path and reference path rather than absolute phase values, the system becomes insensitive to common environmental disturbances while retaining sensitivity to analyte-induced phase changes, thus resolving the contradiction between sensitivity and stability
2Reliability
If a reference optical path is added to suppress noise, then stability is improved, but device complexity increases
Solution Approach 1:
The patent merges the reference optical path and sensing optical path into a single integrated optical system using beam splitters and mirrors. Both paths share common optical components and are processed simultaneously through differential interference contrast microscopy, reducing the need for separate independent systems and minimizing additional complexity while achieving noise suppression
3Loss of information
If phase imaging is performed to map surface reactions, then information completeness is improved, but data collection speed decreases due to low frame rate
Solution Approach 1:
The patent enables continuous real-time phase imaging by implementing a differential measurement system that can operate at high frame rates. The differential interference contrast microscopy approach allows continuous capture of phase distributions across the sensing surface, maintaining information completeness while achieving high-speed data collection through the efficiency of differential detection and modern imaging sensors
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 sensitivity, stability, and data collection speed, enabling accurate 2D mapping of surface reactions and achieving a higher signal-to-noise ratio, thereby improving the detection of biological, biochemical, or chemical characteristics.
Implementation Method 1
a beam splitter configured to divide the light into a first beam and a second beam, wherein the beam splitter allows the first beam to pass therethrough while reflecting the second beam
Implementation Method 2
an SPR sensor unit comprising a sensing surface, wherein the first beam from the splitter is reflected by the sensing surface at least twice and be sent back to the splitter
Implementation Method 3
The system used a combined SPR with total internal reflection (TIR) so that an extra phase shift caused by TIR may be added to a detected signal
Implementation Method 4
a converting unit converting the first beam and the second beam from the reflecting unit into a two-dimensional interference fringe pattern
Data Source
AI summary
Disclosed is an optical sensing device, which comprises a light source emitting a light; a beam splitter; an SPR sensor unit comprising a sensing surface; and a detecting mechanism; and a converting unit converting the first beam and the second beam from the optical device into a two-dimensional interference fringe pattern. From the above-mentioned configuration, an extra phase shift of a detection beam in SPR phase measurement is obtained. The differential measurement approach has shown to achieve a sensitivity figure significantly better than the best result that can be obtained from the prior art in the field of the measurement based on an SPR sensor.