Cylindrical Laser Amplifier Liquid Cooling Thermal Stress Reduction
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Solution Overview
Problem
High-energy laser beam amplifiers using titanium-doped sapphire crystals face issues with thermal effects, mechanical stresses, and transverse lasing effects due to high peak power levels, which are not effectively addressed by cryogenic cooling methods that are expensive, vibration-inducing, and prone to mechanical aberrations.
Innovation Solution
A laser beam amplifying device with a cylindrical crystal and external surface cooling by a liquid, using pump beams with uniform energy distribution and index-matched cooling liquids to minimize thermal and mechanical stresses, and reduce transverse lasing effects, all operable at room temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cryogenic cooling is used to reduce thermal effects, then thermal management is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent replaces the complex mechanical cryogenic cooling system with a simple liquid cooling system that uses convection heat transfer. The laser crystal is cooled by circulating liquid through channels in direct contact with the crystal surface, eliminating the need for cryogenic equipment such as compressors, vacuum pumps, and cryogenic fingers.
Solution Approach 2:
The patent uses inexpensive liquid coolant (such as water or water-glycol mixture) that can be easily replaced and does not require expensive cryogenic infrastructure. The cooling medium is a simple, low-cost substance that achieves effective heat removal without the high operational costs of cryogenic systems.
2Temperature
If cryogenic cooling is used to reduce thermal effects, then thermal management is improved, but vibration increases impairing laser stability
Solution Approach 1:
The patent eliminates the vibration source by replacing the mechanical cryogenic cooling system with a static liquid cooling system. The circulating liquid provides cooling without generating the vibrations inherent in compressor-based cryogenic systems, thereby maintaining laser beam stability.
3Temperature
If cryogenic cooling is used to reduce thermal effects, then thermal management is improved, but mechanical stresses increase causing thermomechanical aberrations
Solution Approach 1:
The patent changes the temperature parameter from cryogenic levels to moderate cooling temperatures using liquid cooling. This moderate temperature reduction is sufficient to manage thermal effects while avoiding the extreme thermal gradients and associated mechanical stresses that occur with cryogenic cooling.
4Temperature
If cryogenic cooling is used to reduce thermal effects, then thermal management is improved, but transverse lasing effects are enhanced
Solution Approach 1:
The patent modifies the temperature parameter to a moderate cooling regime that prevents the formation of sub-cavities between crystal faces. By avoiding extreme cryogenic temperatures, the system maintains conditions that suppress spontaneous transverse lasing while still providing effective thermal management.
5Power
If pump laser energy is increased to raise output energy, then laser power is improved, but thermal effects increase
Solution Approach 1:
The patent introduces liquid coolant as an intermediary heat transfer medium between the laser crystal and the heat sink. This intermediary efficiently carries away the heat generated by high-power pump lasers, enabling high output energy while maintaining manageable thermal conditions in the crystal.
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 configuration reduces thermal and mechanical stresses, minimizes transverse lasing effects, and maintains high-quality amplified laser beams with improved stability and reduced operational costs compared to cryogenic cooling systems.
Implementation Method 1
cooling of the entire external surface by a cooling liquid
Implementation Method 2
use of a matching liquid so as to avoid transverse lasing effects
Data Source
AI summary
The field of the invention is that of high-energy laser beam amplifiers and associated optical pumping devices. The object of the invention is to use an amplifier configuration and a cooling means which do not have the drawbacks of cryogenic systems that have been used up until now and which however make it possible both to obtain an amplified laser beam of high quality and to minimize transverse lasing effects. A laser beam amplifying device according to the invention combines four main principles, which are use of a crystal exhibiting circular symmetry so as to distribute the mechanical stresses radially; cooling of the entire external surface by a cooling liquid, so as to avoid the use of cryogenic techniques; use of a matching liquid so as to avoid transverse lasing effects; and use of pump laser beams with uniform energy distribution.