Flattened Optical Waveguide for Laser Beam Homogenization
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Solution Overview
Problem
Laser photocoagulation systems suffer from spatial laser-beam profiles with 'speckle' causing local thermal elevations and cavitation bubbles in the eye, leading to pain and tissue damage due to inhomogeneous intensity distribution and short measurement pulses.
Innovation Solution
A device with an optical waveguide featuring a fibre core with a flattened cross-section, such as a square or polyangular geometry, which refracts helical beams and excites additional fibre modes, resulting in a homogeneous laser-beam profile and allowing precise focusing on the retina.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional circular fibre core is used, then the laser beam can be transmitted, but the intensity distribution becomes inhomogeneous causing speckle and hotspots
Solution Approach 1:
The patent applies asymmetry by replacing the conventional circular fibre core cross-section with a flattened, square, or polyangular cross-section. This geometric modification transforms the symmetric circular mode structure into an asymmetric multi-mode structure that distributes laser energy more uniformly across the beam profile, eliminating speckle and reducing hotspots while maintaining effective laser transmission.
2Productivity
If short measurement pulses are used for photocoagulation, then treatment speed is improved, but cavitation bubbles form causing pressure transients that mask temperature measurements
Solution Approach 1:
The patent applies parameter changes by modifying the spatial distribution parameters of the laser beam through the flattened fibre core geometry. This changes the mode structure and intensity profile parameters to create a more homogeneous beam that delivers energy uniformly, preventing localized thermal spikes and cavitation bubble formation even during short pulse treatments, thereby enabling accurate temperature measurements.
3Manufacturing precision
If the laser beam is focused to treat retinal tissue, then treatment precision is improved, but inhomogeneous intensity distribution causes local thermal elevations exceeding coagulation temperature
Solution Approach 1:
The patent applies local quality by creating a spatially uniform intensity distribution across the entire laser beam cross-section through the flattened fibre core geometry. This ensures that every local region of the beam delivers consistent energy density, preventing localized thermal elevations and hotspots while maintaining precise focusing capability for retinal treatment.
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 achieves improved homogeneity of the laser-beam profile, reducing local hotspots and cavitation bubbles, enabling precise temperature measurements and minimizing tissue damage during photocoagulation.
Implementation Method 1
an optical waveguide including a fibre core, wherein the edge of the cross-section of the fibre core comprises a straight section
Data Source
AI summary
A device for homogenizing a laser-beam profile and a method for focussing and homogenizing a laser beam in laser photocoagulation for coagulating organic tissue, for example in the eye of a living organism.