Temporal Pulse Splitting for High-Power Laser Compression

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Solution Overview

Problem

High-energy and high peak-power chirped pulse amplification-based laser systems are limited by the grating compressors, which can be damaged by the high-energy and peak-power densities of amplified pulses, leading to a reduced compressor lifetime.

Innovation Solution

A device and method that divide a laser pulse into temporally delayed sub-pulses, which are then compressed and recombined, reducing the energy load on the compressor by distributing it across multiple sub-pulses and using a single compressor section, thereby increasing the compressor's lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a single grating compressor is used to compress high-energy laser pulses, then the laser system achieves high peak power output, but the compressor is damaged by high energy and peak power densities

Engineering Contradiction:
Improvepeak power outputVSAvoidcompressor lifetime
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The laser pulse is divided into multiple temporal sub-pulses using a pulse picker or acousto-optic modulator. Each sub-pulse contains a fraction of the total pulse energy, allowing them to pass through the compressor without exceeding the damage threshold of the grating, while the compressed sub-pulses are later recombined to achieve the desired high peak power output

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple compressors are used in parallel to handle high energy loads, then the compressor lifetime is increased, but the device complexity and need for active stabilization increase

Engineering Contradiction:
Improvecompressor lifetimeVSAvoidcompressor configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using multiple compressors in parallel, the invention segments the input pulse temporally so that a single compressor can handle multiple lower-energy sub-pulses sequentially. This avoids the complexity of synchronizing multiple compressors and their beam paths while still reducing the energy load on the compressor

Inventive Principle:
Principle #1Segmentation

3Productivity

If the laser pulse is compressed directly without division, then the compression efficiency is high, but the energy load on the compressor exceeds its damage threshold

Engineering Contradiction:
Improvecompression efficiencyVSAvoidenergy density damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The pulse is divided into sub-pulses that individually have sufficient energy to maintain good compression efficiency when processed by the compressor, but low enough total energy per sub-pulse to avoid damaging the compressor. The compressed sub-pulses are then recombined to achieve the final high peak power output

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 reduces the energy load on the compressor, increasing its lifetime and allowing for efficient and cost-effective amplification of high-power laser pulses without the need for active stabilization, as the sub-pulses are compressed and combined passively.

Implementation Method 1

The stretching unit can for example comprise a dispersive fiber which result in a temporal broadening of the pulse

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

a polarizing beam splitter dividing a laser pulse into sub pulses, one having a first polarization and another having a second polarization

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 3

These grating compressors can suffer from the high-energy and peak-power densities resulting from the amplified pulses

Methodology Applied
Scientific EffectGrating compression: Diffraction Grating

Data Source

PatentEP4220871B1Device and method for amplifying a laser pulse
Publication Date: 2024.03.13 UNIVERSITAT STUTTGART
  • EP4220871B1 patent drawingFigure 1~2
  • EP4220871B1 patent drawingFigure 3~5
  • EP4220871B1 patent drawingFigure 6~7

AI summary

The invention relates to a device (10) for amplifying a laser pulse which comprises a divider section (14) for dividing the laser pulse into multiple sub pulses (43) and for introducing a time delay between the sub pulses (43), a compressor section (15) for compressing the temporally divided sub pulses (43) and a combiner section (17) for combining the compressed sub pulses (44) to one compressed laser pulse (45).