Multi-Stage DPSSL Amplifier for Efficient Laser Shock Peening

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Solution Overview

Problem

Flashlamp-pumped lasers used in laser shock peening are inefficient, prone to beam distortions, require high operating voltages and currents, have limited operational life, and are cumbersome for transportation due to excess heat and maintenance needs.

Innovation Solution

A diode-pumped solid-state laser (DPSSL) oscillator with a multi-stage amplifier configuration, including a modulator and optical filter, to produce a pulsed laser beam with modified energy and temporal profiles, optimized for laser shock peening, which enhances beam quality and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If flashlamp-pumped lasers are used to produce high energy laser pulses for LSP, then sufficient laser energy is achieved, but electrical efficiency is poor and excess heat is generated

Engineering Contradiction:
Improvelaser energy outputVSAvoidelectrical efficiency
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent changes the pumping method parameter from flashlamp to laser diode, which fundamentally alters the electrical-to-optical conversion efficiency. Laser diodes provide direct stimulated emission with much higher quantum efficiency compared to the broadband flashlamp approach, thereby resolving the electrical efficiency problem while maintaining high laser energy output.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the flashlamp-based pumping mechanism with a laser diode pumping system. This substitution eliminates the inefficiencies of flashlamp broadband emission and improves the overall electrical efficiency of the laser system while maintaining the required high energy output for LSP applications.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Power

If flashlamp-pumped lasers are used to produce high energy laser pulses, then sufficient laser energy is achieved, but beam distortions occur

Engineering Contradiction:
Improvelaser energy outputVSAvoidbeam quality
Core Design Contradiction:
PowerVSManufacturing precision

Solution Approach 1:

The patent changes the pumping source parameter from flashlamp to laser diode, which provides more coherent and controlled pump light. This results in improved beam quality and reduced beam distortions while maintaining the high energy output required for LSP applications.

Inventive Principle:
Principle #35Parameter changes

3Power

If flashlamp-pumped lasers are used, then high operating voltages and currents are required, but this limits operation to locations with industrial service

Engineering Contradiction:
Improvelaser energy outputVSAvoidoperational flexibility
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The patent changes the electrical parameters by using laser diode pumping instead of flashlamp pumping. Laser diodes operate at lower voltages and currents with higher electrical efficiency, which improves operational flexibility and allows the system to be deployed in locations without high-voltage industrial service infrastructure.

Inventive Principle:
Principle #35Parameter changes

4Power

If flashlamp-pumped lasers are used, then laser energy output is achieved, but operational life is limited to several million pulses

Engineering Contradiction:
Improvelaser energy outputVSAvoidoperational life
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent changes the pumping mechanism from flashlamp to laser diode, which has significantly longer operational life and higher reliability. Laser diodes are solid-state devices with no filament or gas discharge components that limit their lifespan, thereby extending the operational life beyond several million pulses while maintaining high laser energy output.

Inventive Principle:
Principle #35Parameter changes

5Power

If flashlamp-pumped lasers are used, then laser energy output is achieved, but the system is cumbersome for transportation due to heat and maintenance needs

Engineering Contradiction:
Improvelaser energy outputVSAvoidsystem portability
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent changes the pumping system from flashlamp to laser diode, which generates significantly less excess heat and requires minimal cooling infrastructure. This reduction in thermal management requirements and maintenance needs simplifies the overall system design and improves portability, making the high-energy laser system more suitable for transportation and field deployment.

Inventive Principle:
Principle #35Parameter changes

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 provides a more efficient, reliable, and portable laser system for laser shock peening by improving beam quality, reducing maintenance needs, and increasing operational flexibility.

Implementation Method 1

A diode-pumped solid-state laser (DPSSL) oscillator may be used to output a pulsed laser beam

Methodology Applied
Scientific EffectStimulated emission: Laser

Implementation Method 2

The modulator may be configured to receive the pulsed laser beam from the DPSSL oscillator, to modify the pulsed laser beam from the first energy to a second energy, and to modify the first temporal profile to a second temporal profile

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 3

The amplifier may have multiple stages. For example, a first stage may be configured to receive the beam having the second energy and the second temporal profile, to amplify the beam from the second energy to a third energy

Methodology Applied
Scientific EffectStimulated emission: Laser

Data Source

PatentEP3588698B1Multi-stage amplifier, method and apparatus for use in laser shock peening processes
Publication Date: 2023.09.06 LSP TECHNOLOGIES INC
  • EP3588698B1 patent drawingFigure 1
  • EP3588698B1 patent drawingFigure 2
  • EP3588698B1 patent drawingFigure 3

AI summary

The invention relates to a multi-stage amplifier comprising a first and second stage each having an amplifier module configured to amplify a laser beam and a vacuum relay imaging module VRIM arranged in a sequential order such that the laser beam passes sequentially through each VRIM and amplifier module to output an amplified beam. The invention also relates to a method of amplifying a laser beam and to an apparatus for laser shock peening comprising an amplifier module.