Laser-Pumped Plasma Light Source Ignition
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Solution Overview
Problem
Existing high-brightness laser-pumped plasma light sources face challenges in achieving reliable and stable plasma ignition due to electrode-related disturbances, complex design, and inefficient laser power utilization, leading to reduced stability and lifetime.
Innovation Solution
A pulsed laser system is used to generate two focused laser beams within a high-pressure gas chamber, where the first beam provides optical breakdown and the second beam ignites and sustains the plasma, ensuring sufficient volume and density for stable operation by a continuous wave laser with reduced power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodes are used for plasma ignition, then plasma ignition reliability is improved, but spatial and energetic stability deteriorates due to convective gas flow disturbances
Solution Approach 1:
The patent removes electrodes from the plasma generation chamber entirely, replacing them with laser-based ignition and sustenance systems. This extraction eliminates the harmful convective disturbances caused by electrodes while maintaining plasma ignition reliability through optical breakdown and laser-sustained plasma techniques.
Solution Approach 2:
The patent replaces the mechanical electrode-based plasma ignition system with an optical/laser-based system. The laser beam creates optical breakdown in the gas to initiate plasma without physical contact, and then sustains the plasma through continuous laser pumping, eliminating mechanical disturbances from electrodes.
2Reliability
If electrodes are placed near the plasma region, then plasma ignition is facilitated, but spatial angles for radiation exit are restricted
Solution Approach 1:
The patent extracts electrodes from the chamber entirely, allowing the plasma to be generated and sustained in the central region without physical obstructions. This provides unobstructed 4π steradian radiation exit in all directions, eliminating the spatial angle restrictions imposed by electrode placement.
3Illumination intensity
If full laser power is used for COD sustenance, then light source brightness is improved, but lifetime is reduced
Solution Approach 1:
The patent employs pulsed laser operation for plasma ignition followed by continuous wave (CW) laser sustenance. This periodic action pattern allows the system to achieve high brightness during plasma generation and maintain it sustainably over extended periods, improving both brightness and lifetime compared to continuous high-power operation.
Solution Approach 2:
The patent changes the laser operating parameters from continuous high power to a combination of pulsed high power for ignition and CW lower power for sustenance. This parameter optimization enables the system to achieve the necessary plasma density for high brightness while reducing the average power load to extend component lifetime.
4Illumination intensity
If laser beam is sharply focused for high brightness, then illumination intensity is improved, but device complexity increases for aligning multiple laser beams
Solution Approach 1:
The patent segments the laser system into two distinct functional components: a pulsed laser for plasma ignition and a CW laser for plasma sustenance. This segmentation allows each laser to be independently optimized and aligned, simplifying the overall alignment process compared to attempting to use a single laser for both functions or combining multiple CW lasers.
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 achieves reliable and stable continuous optical discharge ignition without electrodes, improving chamber design, stability, and lifetime, while allowing for high-brightness broadband radiation with increased spatial and power stability and reduced operational costs.
Implementation Method 1
a first laser beam is arranged for gas optical breakdown
Implementation Method 2
Continuous optical discharge (COD) is a stationary gas discharge sustained by laser radiation in pre-created relatively dense plasma
Implementation Method 3
A COD, sustained by a focused beam of a continuous wave (CW) laser
Data Source
AI summary
The light source contains a gas filled chamber with a region of radiating plasma sustained by a focused beam of a CW laser. The means for plasma ignition is a pulsed laser system generating a first and a second laser beams focused in the chamber. The first laser beam provides the optical breakdown, after which the second laser beam ignites the plasma, whose volume and density are sufficient for stationary plasma sustenance by CW laser after finishing the second laser pulse. Preferably, the first laser beam is generated in Q-switching mode and the second laser beam is generated in free-running mode. The technical result consists in ensuring high reliability of igniting the plasma, in creating in this basis electrodeless high-brightness broadband light sources with the high spatial and power stability, and in providing an ability to collect broadband plasma radiation in a spatial angle of more than 9 sr.