Gap Spectrum OCT Using Overlapping Narrow-Band Sources
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Solution Overview
Problem
High-cost broad band light sources in swept-source OCT systems limit the market to high-end devices, and combining multiple narrow bandwidth lasers to achieve desired resolution is challenging due to spectral gaps and overlaps leading to undesirable sidelobes and detection issues.
Innovation Solution
A method to combine interferometric measurements from multiple narrow-band light sources with overlapping spectra mathematically, achieving higher axial resolution by sequentially illuminating a sample with each source and correcting phase offsets before summing the signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple narrow bandwidth lasers are combined to achieve broad bandwidth for high resolution, then axial resolution is improved, but spectral gaps and overlaps cause undesirable sidelobes and detection issues
Solution Approach 1:
The system segments the broad bandwidth requirement into multiple narrow bandwidth laser sources, each covering a specific wavelength range. These segmented spectral bands are then sequentially activated and combined through mathematical processing to achieve the equivalent of a broad bandwidth source, thereby improving axial resolution while avoiding the sidelobe issues caused by spectral gaps and overlaps
Solution Approach 2:
The system employs periodic action by sequentially activating different narrow bandwidth laser sources in a time-multiplexed manner. Each laser is activated in turn, and the periodic switching between sources allows the system to accumulate spectral information over time, achieving broad bandwidth coverage without the interference problems of simultaneous combination
2Measurement precision
If expensive broad band light sources are used to achieve high resolution, then axial resolution is improved, but system cost increases
Solution Approach 1:
The system replaces expensive broad band light sources with multiple relatively inexpensive narrow bandwidth laser sources. By using affordable, commercially available narrow line lasers and combining them through sequential activation and mathematical processing, the system achieves the same axial resolution performance at a significantly lower cost
Solution Approach 2:
The system merges the capabilities of multiple narrow bandwidth lasers to achieve the performance of a single broad bandwidth source. Through optical combination and mathematical processing of the sequential measurements, the system consolidates the spectral coverage of multiple inexpensive lasers to match or exceed the resolution of expensive broad band sources
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 enables cost-effective swept-source OCT systems with axial resolution exceeding that of individual light sources, reducing costs while maintaining or improving image quality.
Implementation Method 1
A method to combine interferometric measurements from multiple narrow-band light sources with overlapping spectra mathematically, achieving higher axial resolution by sequentially illuminating a sample with each source
Data Source
AI summary
A system, method and/or device for obtaining interferometric measurements using multiple light sources to image, in sequence, a location on a sample, where the light sources have different spectral wavelength bands, and adjacent spectral wavelength bands overlap each other. The respective interferometric measurements are combined mathematically to define a composite interferometric measurement for the location on the sample. The composite interferometric measurement has a greater axial resolution than that of any of the individual light sources.