Laser Amplifier Beam Impact Segmentation

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Solution Overview

Problem

Existing laser amplifier systems face challenges with complex and expensive optical arrangements, long beam propagation leading to stability issues and degradation due to thermal turbulences, and increased beam quality deterioration from nonlinear optical effects, especially in high-energy applications.

Innovation Solution

A method and system where a laser beam is amplified by reflecting multiple times between an optical module and a laser amplifier module, with impact areas smaller than the excited area, allowing for a shorter beam path and even energy extraction from distinct positions within the excited volume, reducing thermal turbulence impact and enabling a simpler, less expensive optical setup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the laser beam is reflected several times to the pump spot using a complex optical arrangement, then the laser beam amplification level increases, but the device complexity and cost increase

Engineering Contradiction:
Improvelaser beam amplification levelVSAvoidoptical arrangement complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention divides the pump spot into multiple distinct impact areas (first impact area, second impact area, etc.) within the excited volume. The laser beam is directed to sequentially impact these distinct areas rather than repeatedly targeting the same spot, enabling multiple amplification passes while simplifying the optical arrangement's positioning requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-point repeated impact approach to a multi-point spatial distribution approach within the excited volume. By utilizing the three-dimensional space of the excited volume and distributing impact areas across different positions and depths, the system achieves multiple amplification interactions without requiring complex optical path folding.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If the laser beam travels a long propagation distance to achieve desired amplification, then the amplification level increases, but the beam stability deteriorates due to thermal turbulences

Engineering Contradiction:
Improvelaser beam amplification levelVSAvoidlaser beam stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The total amplification process is segmented into multiple discrete interaction stages, with the laser beam impacting distinct areas (first impact area, second impact area, etc.) within the excited volume. This segmentation allows the beam to undergo multiple amplification passes over a shorter cumulative path length, reducing exposure to thermal turbulences while achieving the required amplification level.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention maintains continuous interaction between the laser beam and the excited volume by sequentially directing the beam to multiple impact areas within the same excited volume. This continuous useful action ensures that amplification occurs throughout the entire interaction process without requiring the beam to travel long distances between amplification stages, thereby maintaining beam stability.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If the laser beam propagation length is increased for high energy applications, then the amplification level increases, but the beam quality deteriorates due to nonlinear optical effects

Engineering Contradiction:
Improveamplification level for high energy applicationsVSAvoidlaser beam quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The amplification process is divided into multiple discrete interaction segments where the laser beam sequentially impacts distinct areas within the excited volume. This segmentation enables high-energy amplification to be achieved through multiple smaller interaction steps rather than a single long propagation path, thereby reducing the accumulation of nonlinear optical effects and preserving beam quality.

Inventive Principle:
Principle #1Segmentation

4Use of energy by moving object

If the impact area size matches the pump spot size, then the energy extraction is efficient, but the optical arrangement becomes more complex

Engineering Contradiction:
Improveenergy extraction efficiencyVSAvoidoptical arrangement complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

Instead of requiring the laser beam to repeatedly target the same pump spot area, the invention segments the energy extraction process by directing the beam to multiple distinct impact areas within the excited volume. Each impact area is optimized for efficient energy extraction, and the segmentation allows this to be achieved across multiple passes without increasing optical arrangement complexity.

Inventive Principle:
Principle #1Segmentation

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 approach results in stable and efficient laser beam amplification with reduced thermal effects, improved beam quality, and increased amplification levels by optimizing the number and distribution of impact areas within the excited volume.

Implementation Method 1

The excited area and/or the pump spot is usually generated through a pump module, e.g. a laser diode, which excites the laser active medium to store energy within the laser active medium

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

the laser beam is reflected several times with a suitable optical arrangement to the same position of the pump spot by which the laser beam extracts the energy stored within the laser active medium

Methodology Applied
Scientific EffectStimulated emission:

Implementation Method 3

conducting a first amplifying pass by reflecting the laser beam multiple times between the optical module and the laser amplifier module

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3823111B1Method for amplifying a laser beam, laser amplifier system and optical module for use in a laser amplifier system
Publication Date: 2023.06.07 UNIVERSITAT STUTTGART
  • EP3823111B1 patent drawingFigure 1
  • EP3823111B1 patent drawingFigure 2
  • EP3823111B1 patent drawingFigure 3

AI summary

An aspect of the invention relates to a method for amplifying a laser beam in a laser amplifier system (10) including a laser amplifier module (12) and an optical module (14), the method comprising: - generating an excited volume in a laser amplifier module (12) so that a surface (19) of the laser amplifier module (12) facing the optical module (14) includes an excited area (20); - coupling the laser beam (24) into the laser amplifier system (10); - conducting a first amplifying pass by reflecting the laser beam (24) multiple times between the optical module (14) and the laser amplifier module (12), wherein each time the laser beam (24) is reflected from the optical module (14) to the laser amplifier module (14), the laser beam (14) impacts on a respective impact area (I2-I47) of the surface (19) of the laser amplifier module (12), wherein the size of each impact area (I2-I47) is smaller than the size of the excited area (20), and wherein a subset of impact areas of all of the impact areas is located on distinct positions of the excited area (20).