Common Path OCT Probe Reference Reflection Positioning
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Solution Overview
Problem
Optical coherence tomography (OCT) devices face challenges in achieving efficient coupling and controlled reference signal power, leading to suboptimal signal-to-noise ratio (SNR) due to low reference coupling efficiency and variability across different OCT types, which affects imaging quality, especially in imaging luminal and hollow structures.
Innovation Solution
A common path OCT system with a reference reflection positioned to maximize coupling efficiency, utilizing optical coatings and geometric configurations such as tilted lenses and spacers to optimize reference signal power, and employing a probe with a fiber and collimator to efficiently couple light, reducing undesired reflections and aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional OCT systems use separate reference and sample arms with beam splitters, then interference patterns can be generated, but reference coupling efficiency is low and light loss increases
Solution Approach 1:
The patent merges the reference arm and sample arm into a single common optical path by removing the beam splitter. The reference reflection is positioned within the sample arm optics (e.g., on a lens or at the fiber tip), allowing both reference and sample light to propagate through the same optical components and be combined directly at the detector, eliminating the need for separate arms and reducing light loss.
Solution Approach 2:
The patent extracts the beam splitter component from the traditional OCT system architecture. By removing the beam splitter that divides light into separate reference and sample arms, the system achieves higher coupling efficiency and reduces the number of optical interfaces where light loss occurs, while maintaining the necessary interference functionality through in-line reference reflection.
2Measurement precision
If reference signal power is increased to improve SNR, then signal quality improves, but noise from other sources overtakes the SNR
Solution Approach 1:
The patent implements feedback control by continuously monitoring the interference signal quality and dynamically adjusting the reference reflection position or optical properties to maintain optimal reference signal power. This feedback mechanism ensures the reference signal remains strong enough for high SNR while preventing excessive power that would amplify noise, by adapting to real-time measurement conditions.
3Measurement precision
If materials with specific refractive indices are used to control reference signal, then discrete reference signal values are achieved, but continuous control is limited
Solution Approach 1:
The patent changes the control parameter from material selection (discrete refractive indices) to geometric positioning (continuous position along the optical axis). By moving the reference reflection to different positions within the sample arm, the optical path length can be continuously adjusted, providing fine-grained control over the reference signal phase and amplitude, enabling precise depth encoding and continuous signal adjustment.
4Measurement precision
If coatings are used to control reference power over broad range, then signal control improves, but coupling efficiency must be high and deterministic
Solution Approach 1:
The patent changes the control mechanism from relying on coating properties (which require high and deterministic coupling) to geometric positioning of the reference reflection. By adjusting the position of the reference reflector along the optical path, the system achieves broad reference power control without depending on precise coating characteristics, thereby reducing sensitivity to coupling efficiency variations and improving reliability.
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 solution enables efficient geometric coupling and controlled reference signal power, improving SNR and reducing the complexity and cost of OCT devices, while minimizing path length and polarization mismatches, thereby enhancing imaging quality across various OCT types.
Implementation Method 1
generate interference light by causing reflected or scattered light of the first light with which the object or sample has been irradiated and the reflected second reference light to combine or recombine, and/or to interfere, with each other
Implementation Method 2
send the second reference light along a reference arm of the common path interference optical system for reflection off of a reference reflection of the common path interference optical system
Data Source
AI summary
One or more devices, systems, methods and storage mediums for performing common path optical coherence tomography (OCT) with a controlled reference signal and efficient geometric coupling are provided. Examples of such applications include imaging, evaluating and diagnosing biological objects, such as, but not limited to, for Gastro-intestinal, cardio and/or ophthalmic applications, and being obtained via one or more optical instruments, such as, but not limited to, optical probes (e.g., common path probes), common path catheters, common path capsules and common path needles (e.g., a biopsy needle). Preferably, the OCT devices, systems methods and storage mediums include or involve a reference reflection or a reference plane that is at least one of: (i) disposed in the collimation field or path; and (ii) is perpendicular (or normal) or substantially perpendicular (or substantially normal) to light propagation. One or more embodiments may include beam shaping optics to properly image luminal or other hollow structures or objects.