Segmented Ceramic Disk Laser With Cryogenic ASE Suppression

Solution Overview

Problem

Current laser systems face limitations in power scaling due to amplified spontaneous emissions (ASE) and heat management, which reduce beam quality and efficiency, especially as the size of the lasing medium increases, and existing cooling methods like water are inefficient.

Innovation Solution

A substrate with ceramic sections, doped to attenuate light and surrounded by suppression material, is used to manage light intensity and ASE, combined with a cooling system that employs liquid nitrogen to efficiently remove heat from the back side, maintaining lower operating temperatures and reducing ASE.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the size of the lasing medium is increased to achieve higher power output, then power scaling is improved, but beam quality deteriorates due to amplified spontaneous emissions (ASE)

Engineering Contradiction:

Improvepower outputVSAvoidbeam quality

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The lasing medium is divided into multiple separate disks rather than using a single large medium. Each disk is independently pumped and cooled, allowing the system to achieve higher total power output while maintaining beam quality. The segmentation prevents ASE from degrading beam quality by isolating the gain regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each disk in the segmented system has optimized local properties including specific doping concentrations and cooling configurations tailored to its position and function. This allows each local region to operate at optimal conditions for maintaining beam quality while contributing to overall power output.

Inventive Principle:

Principle #3Local quality

2Power

If the lasing medium is increased in size for power scaling, then power output is improved, but heat management becomes more difficult

Engineering Contradiction:

Improvepower outputVSAvoidheat management

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The lasing medium is divided into multiple separate disks rather than using a single large medium. Each disk is independently pumped and cooled, allowing the system to achieve higher total power output while maintaining beam quality. The segmentation prevents ASE from degrading beam quality by isolating the gain regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The operating temperature of the lasing medium is reduced to cryogenic temperatures (e.g., 77K using liquid nitrogen cooling). This parameter change significantly improves the thermal management capability, allowing higher power densities to be sustained without excessive heat buildup, thereby enabling power scaling while maintaining beam quality.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If traditional water-based cooling is used, then cooling capability is limited, but system complexity is low; if cryogenic cooling with liquid nitrogen is implemented, then cooling efficiency is improved, but system complexity increases

Engineering Contradiction:

Improvecooling efficiencyVSAvoidsystem complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The operating temperature of the lasing medium is reduced to cryogenic temperatures (e.g., 77K using liquid nitrogen cooling). This parameter change significantly improves the thermal management capability, allowing higher power densities to be sustained without excessive heat buildup, thereby enabling power scaling while maintaining beam quality.

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

This approach allows for increased beam power while maintaining high beam quality by reducing ASE and heat, using a smaller number of disks with enhanced power amplification and efficient cooling, outperforming traditional water-based cooling methods.

Implementation Method 1

The substrate is configured to reflect the light received on the front side of the substrate

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

a cooling system configured to allow liquid nitrogen to be transmitted through the cooling system and receive heat generated in the substrate from the back side of the substrate

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

each section of the plurality of sections is surrounded by a suppression material configured to attenuate light transmitting through the suppression material

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP2534738B1Disk laser

Publication Date: 2024.03.06 THE BOEING CO

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AI summary

The different advantageous embodiments provide an apparatus and method comprising a substrate (900, 1300) configured to increase an intensity of light at a desired wavelength. The substrate (900, 1300) has a front side (1302), a back side (1304), and an outer edge (922, 1306). The substrate (900, 1300) is configured to reflect the light received on the front side (1302) of the substrate. The substrate comprises ceramic. The substrate (900, 1300) comprises a plurality of sections (902-918). The method and apparatus also comprise a material (920) configured to attenuate the light passing between the plurality of sections (902 -918). The material (920) surrounds an edge of each section of the plurality of sections. The apparatus and method also comprise a cooling system (808) configured to allow liquid nitrogen to be transmitted through the cooling system (808) and receive heat generated in the substrate (900, 1300) from the back side (1304) of the substrate (900, 1300).