Laser Resonant Cavity Microstructure for Beam Divergence
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Solution Overview
Problem
High power lasers often exhibit 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, such as a spherical mirror with a metal film and a concaved hole or array of holes, within a resonant cavity to produce a laser beam with a small divergence angle, long depth of focus, and low power density loss, achieved by optimizing the curvature radius, microstructure size, and material selection.
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 changes the geometric parameters of the resonant cavity, specifically using a spherical mirror with optimized curvature radius (R=0.5-5m) and controlling the cavity length (L=0.5-2m) to achieve single-mode operation at high power levels, thereby reducing beam divergence while maintaining high power output
Solution Approach 2:
The patent employs a spherical mirror instead of conventional flat or parabolic mirrors, with the spherical curvature radius specifically optimized to achieve stable resonant cavity operation and improved beam quality with smaller divergence angles at high power levels
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 patent optimizes the resonant cavity parameters including spherical mirror curvature radius (R=0.5-5m) and cavity length (L=0.5-2m) to achieve a balance between high power output and long depth of focus, enabling the laser to maintain focused beam over extended distances
Solution Approach 2:
The spherical mirror geometry with optimized curvature provides stable resonant modes that produce laser beams with extended depth of focus, allowing the high power beam to remain concentrated over longer propagation distances
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 patent optimizes the resonant cavity parameters (spherical mirror curvature radius R=0.5-5m, cavity length L=0.5-2m) to generate single-mode laser beams with improved beam quality factor, which significantly reduces power density loss during long distance transmission while maintaining high power output
Solution Approach 2:
The spherical mirror with optimized curvature radius creates stable resonant modes that produce laser beams with reduced diffraction and lower power density loss over long transmission distances, enabling efficient energy delivery
4Device complexity
If conventional resonant cavity design is used, then device complexity is low, but beam quality is poor
Solution Approach 1:
The patent uses a spherical mirror with specifically optimized curvature radius (R=0.5-5m) in the resonant cavity, which improves beam quality by enabling stable single-mode operation while maintaining a relatively simple cavity structure with only two mirrors
Solution Approach 2:
The patent optimizes key parameters including spherical mirror curvature radius (R=0.5-5m), cavity length (L=0.5-2m), and mirror aperture ratios to achieve high beam quality with small divergence angles while keeping the device structure simple and practical
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 resulting laser beam has a high quality, long depth of focus, and high power density, enabling efficient applications in cutting, welding, and long distance transmission with reduced power loss.
Implementation Method 1
a resonant cavity 110, wherein the active laser medium 108 is filled in the resonant cavity 110
Implementation Method 2
a total reflective mirror 102...the total reflective mirror 102, the output mirror 104, and the discharge lamp 106 define a resonant cavity 110
Implementation Method 3
an output mirror 104...configured on two opposite ends of the discharge lamp 106
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 body, a metal film, and at least one microstructure. The at least one microstructure is concaved from a first reflective surface of the total reflective mirror. The at least one microstructure has a depth and a lateral size, and both the depth and the lateral size are in a range from about 0.5λ to about 2λ, while λ is a working wavelength of the laser.