SPR Optical Source Narrow Line Width Filter
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Solution Overview
Problem
Surface Plasmon Resonance (SPR) systems face challenges in achieving high resolution and accuracy due to the Signal to Noise Ratio (SNR) issues caused by the broad spectrum of incoherent light sources like LEDs, and the high power coherent light from lasers introduces optical interference, degrading the ability to measure minute refractive index changes.
Innovation Solution
An SPR system utilizing an innovative incoherent light source with a source line width of approximately 0.1 nm to 20 nm, combined with an optical power amplifier-filter, to produce high sensitivity measurements by minimizing noise and interference, while maintaining sufficient optical power for accurate analyte detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an incoherent light source like LED is used, then the system is simple and cost-effective, but the broad spectrum causes poor signal to noise ratio and low measurement precision
Solution Approach 1:
The patent applies parameter changes by transforming the light source characteristics from broad-spectrum incoherent light to narrow-line-width light through spectral filtering. The filter selectively transmits a narrow wavelength range (line width 0.1-20 nm) while blocking other wavelengths, thereby improving measurement precision without requiring a complete system redesign. This resolves the contradiction by modifying the spectral parameter of the light source.
2Measurement precision
If the power of an incoherent light source is increased, then the signal to noise ratio improves moderately, but the inherent design of LEDs limits the maximum power density
Solution Approach 1:
The patent extracts only the necessary spectral component from a broader spectrum light source using a narrow-band filter. By taking out the specific wavelength range needed for SPR measurement (line width 0.1-20 nm), the system achieves high signal-to-noise ratio with optimized power density, avoiding the limitation of LED's inherent maximum power output while maintaining incoherent light advantages.
3Measurement precision
If a laser is used to provide high power density, then resolution improves, but coherent light introduces optical interference and standing wave patterns that degrade measurement accuracy
Solution Approach 1:
The patent converts the harmful effect of coherence into a benefit by using incoherent light with narrow line width. Instead of using coherent laser light that creates standing wave patterns, the system uses filtered incoherent light that maintains narrow spectral width without coherence-induced interference. This approach achieves high resolution while eliminating the harmful standing wave effects, effectively turning the limitation of incoherent light into an advantage.
4Measurement precision
If a narrow line width light source is used, then measurement precision improves, but the optical power may be insufficient for high sensitivity detection
Solution Approach 1:
The patent optimizes the balance between power and precision by carefully controlling the line width parameter within the range of 0.1-20 nm. This parameter optimization allows the system to achieve sufficient spectral resolution for high-precision measurement while maintaining adequate optical power for sensitive detection, resolving the contradiction between narrow bandwidth and power availability.
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 system achieves improved resolution and accuracy in measuring refractive index changes, enabling better detection of binding analytes by optimizing the light source's spectral width and power, thus enhancing the sensitivity and reliability of SPR measurements.
Implementation Method 1
An optical source generates an incoherent light beam with a source line width of about 0.1 nm to 20 nm
Implementation Method 2
Surface Plasmon Resonance (SPR) is a physical phenomenon that is commonly used to investigate the binding properties of chemical and biological molecules. Analytes may bind to immobilized probe molecules on a metal film, altering a resonance characteristic of the surface plasmon and changing the refractive index around the metal film
Implementation Method 3
The detector receives the reflected light. These changes can be measured as an angle shift or alternatively, as a wavelength shift
Data Source
AI summary
The use of a high power and an incoherent light source to reduce noise associated when investigating unknown molecules in Surface Plasmon Resonance (SPR) systems. High power and incoherent light sources can improve resolution and accuracy of SPR system measurements.