Multimode Fiber 3D Beam Scanning via Spatial Light Modulator
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Solution Overview
Problem
Current optical fiber-based endoscopes are limited by their size and inability to scan in three dimensions, restricting their use in sensitive areas and deep tissue imaging due to the large diameter of fiber bundles and limited control over optical modes.
Innovation Solution
The use of a multimode optical fiber with a spatial light modulator to control the relative phase and amplitude of optical modes, enabling beam steering and focusing in a three-dimensional scan region by manipulating the spatial phase and amplitude of the light signal at the input facet of the fiber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bundle of single-mode optical fibers is used to enable three-dimensional beam scanning, then the ability to focus and scan in 3D is improved, but the device diameter becomes too large for insertion into sensitive tissue areas
Solution Approach 1:
The invention segments the function of beam scanning across multiple single-mode fibers into a single multimode fiber by controlling multiple optical modes within one fiber. Instead of using thousands of separate fibers, the patent excites and controls hundreds of modes in a single fiber to achieve the same 3D scanning capability, reducing the device diameter from hundreds of micrometers to tens of micrometers.
Solution Approach 2:
The invention merges the functionality of multiple single-mode fibers into a single multimode fiber. By combining multiple optical modes within one fiber core and controlling their interference patterns, the system achieves three-dimensional beam scanning without requiring a physical bundle of fibers, thus consolidating the structure and reducing size.
2Length of stationary object
If a single multimode optical fiber is used to reduce device size, then the device diameter is reduced for tissue insertion, but the ability to control optical modes for precise beam scanning is limited
Solution Approach 1:
The invention introduces a spatial light modulator (SLM) as an intermediary device at the input end of the multimode fiber. The SLM precisely controls the spatial distribution of optical fields, enabling independent manipulation of hundreds of optical modes. This intermediary allows complex mode control without requiring direct mechanical manipulation of the fiber, thus maintaining ease of operation despite the reduced fiber size.
Solution Approach 2:
The invention replaces mechanical control methods with optical field control. Instead of physically manipulating the fiber or using mechanical scanners, the system uses a spatial light modulator to control the spatial phase and amplitude of optical fields, which then selectively excite desired modes in the multimode fiber. This substitution enables precise control without mechanical complexity.
3Ease of manufacture
If conventional endoscope designs are used, then the structure is simple and easy to manufacture, but the image quality and scanning precision are insufficient for deep tissue imaging
Solution Approach 1:
The invention introduces dynamic control of optical modes through a spatial light modulator, allowing real-time adjustment of beam position, focus, and shape. The system can dynamically switch between different mode combinations to scan across three-dimensional space and adjust focal depth, providing adaptive control that significantly improves imaging precision while maintaining a relatively simple fiber-based structure.
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
Enables precise scanning and focusing of the output beam in a three-dimensional space, improving image quality and allowing for smaller, more versatile imaging systems suitable for sensitive applications like deep tissue imaging and optogenetics.
Implementation Method 1
The different optical modes supported by the fiber reflect from the core/cladding interface at different angles and, therefore, travel different total distances through the fiber. The different modes can emerge from the output facet of the fiber with slightly different phase, launch angle, and from different locations on the output facet.
Implementation Method 2
An optical fiber guides light within a core that is surrounded by a cladding that serves to confine light within the core via a process referred to as 'total internal reflection.' In other words, as the light travels down the fiber, the interface between the core and the cladding acts like a mirror that reflects light rays back into the core material
Implementation Method 3
An optical fiber guides light within a core that is surrounded by a cladding that serves to confine light within the core via a process referred to as 'total internal reflection.'
Implementation Method 4
The present invention enables scanning of an output beam emerging from a multi-mode optical fiber. In some embodiments, the invention enables focusing of the output beam at any point within a three dimensional scan region.
Data Source
AI summary
A method for imaging a scan region by controlling at least one of the relative phase and relative amplitude of multiple optical modes propagating through a multimode optical fiber to control the position of an output beam emitted from the output facet of the optical fiber is disclosed.