Microscope Laser Illumination via Optical Fiber Coherence Control
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Solution Overview
Problem
Laser light sources in microscopes produce a random speckle pattern due to high temporal coherence, which degrades image quality and requires complex systems to mitigate.
Innovation Solution
A microscope system using a laser light source with illumination light propagated through a plurality of optical fibers, where each fiber is longer than the coherence length of the light and may differ in length by at least the coherence length, reducing speckle patterns and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If laser light source is used for illumination, then illumination intensity is improved, but speckle pattern is generated degrading image quality
Solution Approach 1:
The patent divides the single laser light source into multiple separate optical paths by using a bundle of optical fibers. Each fiber carries a portion of the laser light independently, and the fibers have different lengths to introduce random phase shifts. This segmentation approach maintains the high illumination intensity of laser light while reducing the speckle pattern through coherent averaging of multiple independent paths.
Solution Approach 2:
The patent changes the physical parameter of optical path length by using optical fibers with different lengths. This introduces random phase shifts between the light waves from different fibers, which destroys the temporal coherence that causes speckle patterns. The parameter change is applied to the propagation path rather than the light source itself, preserving illumination intensity while eliminating the harmful speckle effect.
2Object-affected harmful factors
If complex systems are used to mitigate speckle pattern, then image quality is improved, but device complexity increases
Solution Approach 1:
The patent introduces optical fibers as an intermediary element between the laser light source and the sample. These fibers serve as mediators that randomly distribute the laser light in both space and phase domains. This intermediary approach simplifies the system compared to complex active mitigation devices while effectively reducing speckle patterns through the inherent randomizing properties of the fiber bundle.
Solution Approach 2:
The patent replaces complex mechanical or active optical systems (such as rotating diffusers, vibrating mirrors, or acousto-optic modulators) with a passive optical fiber bundle. The random phase shifts are achieved through the static but varied optical path lengths of the fibers, eliminating the need for moving parts or complex control systems while maintaining speckle reduction effectiveness.
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 effectively reduces the speckle pattern associated with laser light sources while maintaining higher illumination intensity and ease of integration, leading to improved image quality and light efficiency.
Implementation Method 1
illumination light from a laser light source is propagated toward an observation sample via a plurality of optical fibers
Implementation Method 2
Each optical fiber is longer than a coherence length of the illumination light
Implementation Method 3
Laser light sources in microscopes produce a random speckle pattern due to high temporal coherence
Implementation Method 4
produce a random speckle pattern due to high temporal coherence
Data Source
AI summary
A microscope system includes a laser light source to emit illumination light toward an observation sample. A plurality of optical fibers are disposed along an optical path between the laser light source and the observation sample, such that each optical fiber of the plurality of optical fibers propagates illumination light toward the observation sample. Each optical fiber of the plurality of optical fibers is longer than a coherence length of the illumination light. A first optical fiber of the plurality of optical fibers has a first length that differs from a second length of a second optical fiber by at least the coherence length.