Gas Laser Corner Housing Temperature Control
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Solution Overview
Problem
Gas lasers, particularly those with long resonator lengths, experience undesirable changes in laser beam direction due to temperature gradients causing mirror tilting, which deteriorate beam quality.
Innovation Solution
An additional laser gas cooling device and coolant temperature control system are implemented to maintain a minimal temperature difference between the laser gas and the cooling fluid, typically less than 5 K, 2 K, or 0.2 K, by using separate coolant circuits, expansion devices, Peltier elements, and direct cooling methods to stabilize the corner housings and mirror elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the laser gas is cooled by a heat exchanger circuit with cooling channels in feed lines, then the laser gas temperature is reduced, but a temperature difference of about 10 K remains between the cooled laser gas and the cooling fluid in corner housings, causing asymmetrical expansion and mirror tilting
Solution Approach 1:
The cooling system is divided into separate cooling circuits: one for the laser gas feed lines and another for the corner housings. This segmentation allows independent temperature control of each component, preventing the temperature difference that causes asymmetrical expansion and mirror tilting.
Solution Approach 2:
A temperature control device is introduced as an intermediary between the cooling fluid supply and the corner housing cooling channels. This device actively regulates the cooling fluid temperature to match the laser gas temperature, eliminating the harmful temperature gradient.
2Loss of energy
If the corner housing is cooled by cooling channels with cooling fluid flow, then heat is removed from the corner housing, but the temperature gradient between incoming laser gas and cooling fluid causes asymmetrical expansion of the corner housing
Solution Approach 1:
The temperature parameter of the cooling fluid is dynamically adjusted to match the laser gas temperature. By changing the cooling fluid temperature parameter, the system removes heat from the corner housing while maintaining temperature uniformity, thus preventing asymmetrical expansion and preserving housing symmetry.
3Temperature
If mirror elements are arranged in corner housings with cooling channels, then the corner housings can be cooled, but temperature differences cause tilting of the mirror elements which changes laser beam direction
Solution Approach 1:
A feedback control system is implemented where temperature sensors monitor the laser gas temperature and the cooling fluid temperature, and the temperature control device adjusts the cooling fluid temperature based on this feedback. This closed-loop control maintains temperature uniformity, preventing mirror tilting and ensuring precise beam direction.
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 effectively prevents mirror tilting and stabilizes the laser beam direction, enhancing beam quality by ensuring temperature stability and minimizing the influence of additional heat sources.
Implementation Method 1
one or more cooling channels of a heat exchanger circuit are typically arranged in the feed lines to cool down the laser gas prior to entry into the corner housings
Implementation Method 2
coolant temperature control device for producing a temperature difference between the cooling fluid in the at least one cooling channel of the heat exchanger circuit and the cooling fluid in the at least one cooling channel of the corner housing
Implementation Method 3
additional laser gas cooling device for cooling the laser gas
Data Source
AI summary
A gas laser includes discharge tubes connected to together by corner housings, each corner housing including a first cooling channel configured to allow flow of a first coolant. A heat exchanger circuit includes a plurality of second cooling channels configured to allow flow of a second coolant. Each second cooling channel is operable to cool laser gas prior to the laser gas entering into one of the corner housings. The gas laser further includes a temperature control device, in which the temperature control device is selected from the group consisting of a laser gas cooling device, a coolant temperature control assembly, and combinations thereof. The temperature control device is operable to maintain a temperature difference of less than approximately 5 K between the first coolant flowing through the first cooling channel of the corner housing and the laser gas entering into the corner housing.