Laser Mirror Microstructure for Beam Divergence Control
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Solution Overview
Problem
High power lasers often have large divergence angles, shallow depth of focus, and high power density loss during long distance transmission due to their multi-mode nature, making them unsuitable for precise industrial and military applications.
Innovation Solution
The design incorporates a total reflective mirror with a microstructure and a specific configuration of reflective surfaces to produce a laser beam with a small divergence angle, long depth of focus, and low power density loss, achieved by using a spherical mirror with a metal film and microstructures that enhance surface plasma resonance within the resonant cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power multi-mode lasers are used to achieve high power levels, then power output is improved, but beam divergence angle increases and depth of focus decreases
Solution Approach 1:
The patent segments the laser cavity into multiple sections with different mirror configurations. The resonant cavity includes a total reflective mirror with microstructures and an output mirror arranged to create specific optical paths that segment the beam propagation, allowing high power generation while maintaining beam quality through controlled segmentation of the optical field.
Solution Approach 2:
The patent employs spherical mirrors with specific curvature radii in the resonant cavity. The total reflective mirror and output mirror are configured with curved surfaces that focus and control the laser beam, reducing divergence angle while maintaining high power output through the focusing effect of the spherical geometry.
2Power
If high power multi-mode lasers are used to achieve high power levels, then power output is improved, but depth of focus becomes shallow
Solution Approach 1:
The spherical mirrors with optimized curvature radii extend the depth of focus by creating a longer focal region. The curved reflective surfaces focus the laser beam over an extended distance, maintaining high power density throughout a longer propagation path, thus increasing depth of focus while preserving high power output.
Solution Approach 2:
The patent optimizes parameters including mirror curvature radius, cavity length, and microstructure dimensions to achieve the desired balance between power output and depth of focus. By adjusting these parameters, the system extends the depth of focus while maintaining high power levels through precise control of the optical resonance conditions.
3Power
If high power multi-mode lasers are used to achieve high power levels, then power output is improved, but power density loss increases during long distance transmission
Solution Approach 1:
The segmented cavity design with specific mirror arrangements creates multiple optical paths that reinforce each other, maintaining beam intensity over long distances. The segmentation allows the laser to operate at high power while the distributed optical paths reduce energy loss through constructive interference and controlled beam propagation.
Solution Approach 2:
The spherical mirrors focus the laser beam during transmission, counteracting natural beam divergence and reducing power density loss over distance. The curved reflective surfaces continuously refocus the beam, maintaining high power density during long distance transmission while preserving high power output.
4Shape
If microstructures are added to the total reflective mirror to enhance surface plasma resonance, then beam quality is improved, but device complexity increases
Solution Approach 1:
The microstructures are localized to specific regions of the total reflective mirror surface rather than covering the entire mirror. This local modification enhances surface plasma resonance and beam quality only where needed, while the rest of the mirror maintains its simple reflective function, thus improving beam quality with minimal increase in overall device complexity.
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 results in a high-quality laser beam with a long depth of focus and high power density, suitable for applications like cutting and welding, especially over long distances, by minimizing beam divergence and power loss.
Implementation Method 1
a total reflective mirror with a microstructure and a specific configuration of reflective surfaces to produce a laser beam with a small divergence angle, long depth of focus, and low power density loss, achieved by using a spherical mirror with a metal film and microstructures that enhance surface plasma resonance within the resonant cavity
Implementation Method 2
using a spherical mirror with a metal film and microstructures that enhance surface plasma resonance within the resonant cavity
Data Source
AI summary
A laser includes a total reflective mirror, an output mirror, a discharge lamp, and an active laser medium. The total reflective mirror, the output mirror, and the discharge lamp define a resonant cavity. The active laser medium is filled in the resonant cavity. The total reflective mirror includes a microstructure. The microstructure is convex ring-shaped structure. The convex ring-shaped structure has a height and a width, and both the height and the width are in a range from about 0.5λ to about 2λ, while λ is a working wavelength of the laser.