Single-Channel Polarization-Sensitive OCT Using Orthogonal Reference Paths
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Solution Overview
Problem
Conventional Polarization Sensitive Fourier Domain Optical Coherence Tomography (PS-FD-OCT) systems require dual-channel detection paths, which are costly and prone to misalignment artifacts, necessitating precise alignment and increased monetary cost due to additional detection elements.
Innovation Solution
Implementing at least two reference paths with a difference in optical path length or time delay, each associated with a mutually orthogonal polarization state, allowing for single-channel detection of interference fringes for two orthogonal polarization modes, reducing the need for dual-channel systems and minimizing misalignment artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual-channel detection paths are used to capture spectral interferograms for two orthogonal polarization modes, then polarization sensitivity is achieved, but system cost and alignment complexity increase substantially
Solution Approach 1:
The patent combines the detection of two orthogonal polarization modes into a single detection channel by using a polarization beam splitter to separate the polarization states and a single spectrometer to detect both modes sequentially or simultaneously, eliminating the need for two separate detection channels while maintaining polarization sensitivity
Solution Approach 2:
The patent introduces a polarization beam splitter as an intermediary element that separates the incoming light into two orthogonal polarization components, which are then directed to different detection paths or detected sequentially by a single spectrometer, enabling polarization discrimination without requiring dual-channel detection systems
2Reliability
If dual-channel detection paths are used for PS-FD-OCT, then polarization information can be captured, but misalignment artifacts such as birefringence offset occur due to alignment difficulties
Solution Approach 1:
By merging the detection of both polarization modes into a single detection channel with a shared optical path, the patent eliminates the relative alignment issues between separate channels, as there is only one detection path to align, thereby removing the source of misalignment artifacts like birefringence offset
Solution Approach 2:
The patent uses a single detection channel to capture spectral interferograms that contain information from both polarization modes, effectively creating a unified detection copy that avoids the alignment problems inherent in separate dual-channel systems
3Reliability
If two separate spectrometers or line-scan cameras are used to detect orthogonal polarization modes in parallel, then polarization sensitivity is achieved, but monetary cost increases substantially
Solution Approach 1:
The patent merges the functionality of two separate spectrometers or line-scan cameras into a single spectrometer that detects both orthogonal polarization modes, reducing the number of detection elements from two to one while maintaining the capability to capture polarization information
Solution Approach 2:
The single spectrometer in the patent is designed to detect both orthogonal polarization modes, making it a multi-functional device that performs the work of two separate single-function detectors, thereby reducing system cost and component quantity
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 reduces the effective imaging depth by a factor of two while acquiring polarization information with a single spectrum acquisition, lowering costs and improving system stability by eliminating the need for precise dual-channel alignment.
Implementation Method 1
light from a broad band light source is split by an optical fiber splitter
Implementation Method 2
The reflected light from the scanning device is recombined with the signal from the reference mirror forming interference fringes
Implementation Method 3
A polarization beam splitter is used to separate the orthogonal polarized light
Data Source
AI summary
Provided herein are systems, methods, and compositions for optical coherence tomography implementations. The OCT implementation generally applies to both spectrometer-based and swept source-based implementations of PS-FD-OCT, and also to both fiber based and bulk-optical and Michelson and Mach-Zender PS-OCT implementations, where the detection arm is free from two photoreceivers or spectrometers for detecting the interference of the first polarization state and the second polarization state.