Laser Amplifier Intensity Profile Matching

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Solution Overview

Problem

Current laser amplification methods are limited by thermal effects and require complex structures, leading to high costs and inefficiencies, especially when trying to achieve high-power, high-beam-quality laser radiation for applications like laser annealing.

Innovation Solution

A method and amplifier design that uses a transformer element to adapt the seed laser radiation to match the dimensions of the laser-active amplifier medium, allowing for efficient amplification in a single pass by optimizing the intensity profile to match the gain function profile, thereby reducing thermal effects and eliminating the need for reflector elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the laser-active amplifier medium is traversed multiple times by seed laser radiation to improve amplification efficiency, then the extraction efficiency increases, but the device complexity increases due to the need for reflector elements and complex setup

Engineering Contradiction:
Improveextraction efficiencyVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The amplifier medium is divided into multiple regions with different gain function profiles, allowing the seed laser radiation to be amplified in stages across different spatial zones without requiring physical reflectors to redirect the beam back through the medium

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the one-dimensional multiple-pass amplification approach into a two-dimensional or three-dimensional spatial utilization approach, where the beam passes through the medium once but utilizes multiple gain regions simultaneously, achieving equivalent or superior extraction efficiency without complex optical paths

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

2Productivity

If reflector elements are used to redirect seed laser radiation back into the amplifier medium for multiple passes, then amplification efficiency improves, but the structural complexity and cost increase

Engineering Contradiction:
Improveamplification efficiencyVSAvoidstructural complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the reflector elements from the amplification system, replacing them with a directly coupled amplifier medium that has optimized gain distribution, thereby simplifying the structure while maintaining or improving amplification efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

An adapter element is introduced as an intermediary component that couples the seed laser radiation directly to the amplifier medium with optimized spatial and intensity profile matching, eliminating the need for reflector elements and complex optical paths

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the seed laser radiation intensity profile is not adapted to the amplifier medium dimensions, then the setup is simpler, but the extraction efficiency decreases because only a portion of the pumped energy is utilized

Engineering Contradiction:
Improvesetup simplicityVSAvoidextraction efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent changes the intensity profile parameter of the seed laser radiation to match the gain function profile of the amplifier medium, ensuring optimal spatial and intensity distribution for maximum energy extraction without complicating the setup

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The seed laser radiation is pre-conditioned with an intensity profile that is optimized for the amplifier medium before entering the medium, ensuring that the full pumped energy is utilized from the first pass without requiring multiple reflections or complex adjustments

Inventive Principle:
Principle #10Preliminary action

4Power

If high pumping power is applied to the laser-active amplifier medium to achieve high-power output, then the output power increases, but thermal effects increase which can lead to destruction of the amplifier medium

Engineering Contradiction:
Improveoutput powerVSAvoidthermal effects
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The patent employs pulsed or periodic pumping schemes that allow the amplifier medium to be pumped in cycles with sufficient cooling intervals, enabling high peak power output while managing thermal accumulation and preventing medium destruction

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies localized cooling or thermal management to specific high-stress regions of the amplifier medium, allowing high pumping power to be applied in those areas without causing thermal damage, thereby enabling high overall output power

Inventive Principle:
Principle #3Local quality

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 achieves higher extraction efficiency (30-60%) with reduced thermal effects, allowing for cost-effective amplification of high-power laser radiation while maintaining beam quality, and can be implemented in a simpler, more compact structure.

Implementation Method 1

a beam-side transformer element (3) transforms a transverse seed laser intensity profile (4.1, 4.2) of the seed laser radiation (4) into a plateau-shaped input intensity profile (5.1, 5.2)

Methodology Applied
Scientific EffectBeam transformation: Lens

Implementation Method 2

a laser-active amplifier medium (2), during propagation of the transformed seed laser radiation (5) through the laser-active amplifier medium (2), amplifies the transformed seed laser radiation (5)

Methodology Applied
Scientific EffectLaser amplification: Laser

Implementation Method 3

Energy is deposited in the pump channel (2.4) of the amplifier medium (2) by a pump laser beam (9)

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Data Source

PatentEP3707787B1Laser amplification method
Publication Date: 2023.08.09 AMPHOS
  • EP3707787B1 patent drawingFigure 1~4
  • EP3707787B1 patent drawingFigure 2

AI summary

The invention relates to a method for amplifying seed laser radiation which is irradiated along an irradiation direction into a lasing amplification medium and which has a transverse seed laser intensity profile that is transformed into a plateaued input intensity profile by a transformer element on the irradiation side.