Hollow-Core Fiber Microprobe for Tight Laser Focusing
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Solution Overview
Problem
Existing focusing microprobes face challenges in delivering intense laser beams efficiently to tissues while minimizing optical losses, achieving tight focusing, and operating in contact or near-contact modes, especially in sensitive applications where conventional single-mode fibers are not well-developed for mid-IR wavelengths.
Innovation Solution
The use of hollow-core fiber microprobes with a focusing tip comprising a dielectric microsphere or linear chain of microspheres for flexible and efficient delivery of single-mode or multi-mode laser radiation, allowing for high optical throughput and tight beam focusing in contact or near-contact modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multi-modal delivery systems are used to increase total transmitted power, then power transmission is improved, but focal spot size increases
Solution Approach 1:
The patent segments the optical delivery system into distinct functional components: a multi-mode fiber for power transmission and a single-mode fiber for focused delivery. This segmentation allows each component to optimize for its specific function, resolving the contradiction between power transmission and focal spot size.
Solution Approach 2:
The patent introduces an intermediary optical system including mode converters and beam combining optics that bridge the multi-mode fiber and single-mode fiber. This intermediary system transforms the multi-mode output into a focused single-mode beam, enabling both high power transmission and tight focusing.
2Adaptability or versatility
If flexible optical delivery systems are used to enable curved beam paths, then adaptability is improved, but optical losses increase
Solution Approach 1:
The patent uses a single-mode fiber as an intermediary delivery component that maintains beam quality while being flexible. The single-mode fiber's small core diameter and controlled numerical aperture allow it to transmit light with minimal loss while maintaining the ability to follow curved paths.
Solution Approach 2:
The patent optimizes the numerical aperture parameter of the single-mode fiber to balance flexibility and loss. By controlling the NA within specific ranges, the system achieves sufficient flexibility for curved paths while minimizing optical losses through optimized mode confinement.
3Area of moving object
If conventional single-mode fibers are used for tight focusing, then focal spot size is reduced, but availability for mid-IR wavelengths is limited
Solution Approach 1:
The patent uses a multi-mode fiber as an intermediary for light collection and transmission at mid-IR wavelengths where single-mode fibers are unavailable. The multi-mode fiber captures and transports the laser light to a conversion system that prepares it for single-mode focused delivery, bridging the wavelength gap.
Solution Approach 2:
The patent employs mode converters that transform the spatial distribution of light modes to match the single-mode fiber requirements. This parameter transformation enables the system to achieve tight focusing at mid-IR wavelengths by converting multi-mode input into a fundamental mode output, overcoming the wavelength limitation.
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 solution enables efficient, high-power, and precise laser delivery with reduced focal spot sizes, suitable for ultraprecise surgeries and other applications, while being robust and easy to integrate with existing surgical tools, and capable of operating in liquid environments.
Implementation Method 1
The hollow-core fiber provides for flexible and efficient delivery of the single-mode or multi-mode laser radiation
Implementation Method 2
The focusing tip includes a lens, such as a (dielectric) microsphere or several (dielectric) microspheres assembled in a linear chain. The tip focuses the laser radiation down to diffraction limited beam diameters
Data Source
AI summary
A focusing microprobe system, comprising: one of a single-mode laser radiation source and a few-mode laser radiation source; a coupler coupled to the laser radiation source; one of a single-mode flexible laser radiation delivery system and a few-mode flexible laser radiation delivery system coupled to the coupler; and one or more focusing microlenses coupled to the flexible laser radiation delivery system and arranged in a focusing tip. The coupler comprises a focusing lens. The flexible laser radiation delivery system comprises one of a hollow-core fiber and a flexible waveguide. Optionally, the one or more focusing microlenses are bonded to seal a hollow internal cavity of the flexible laser radiation delivery system. The one or more focusing microlenses comprise one or more conventional lenses or one or more focusing spheres, hemispheres, or cylinders.