Cylindrical Drum Plasma Light Source Laser Damage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Plasma-based light sources face challenges in preventing laser-induced damage to the drum coated with Xenon ice, leading to stability degradation and contamination in the vacuum chamber due to high laser power density and particle propagation.
Innovation Solution
A plasma-based light source with a cylindrically-symmetric element coated with a band of plasma-forming target material, utilizing a system that outputs trimmed laser pulses with controlled intensity profiles and angles to reduce irradiation damage, and incorporating a pre-pulse and main pulse configuration to precondition the target material, along with a focusing unit to direct the laser beam to a waist at a distance from the surface, and grooved surface features to protect the target material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high laser power density is used to generate plasma from Xenon ice target material, then plasma generation efficiency and light output are improved, but laser-induced damage to the drum surface occurs leading to stability degradation and contamination
Solution Approach 1:
A pre-pulse is applied before the main laser pulse to precondition the Xenon ice target material. This preliminary action creates an optimal plasma formation state that allows the main pulse to generate sufficient plasma with reduced peak power density, thereby preventing drum surface damage while maintaining plasma generation efficiency
Solution Approach 2:
The laser system operates with periodic pulsed sequences consisting of pre-pulses followed by main pulses. This periodic action with controlled timing allows the target material to be prepared in each cycle, enabling sustained operation without cumulative damage to the drum surface
2Productivity
If the drum rotates at high speed to continuously present fresh target material, then target material replenishment is improved, but particle propagation and contamination in the vacuum chamber increase
Solution Approach 1:
The drum surface is designed with localized grooves that create specific interaction regions between the laser beam and target material. This local structural modification confines particle generation to specific zones, reducing overall particle propagation and contamination while maintaining effective target material presentation
Solution Approach 2:
The grooved structure on the drum surface acts as an intermediary between the laser beam and target material. These grooves modify the plasma formation process and particle ejection patterns, serving as a mediator that reduces harmful particle propagation while maintaining target material effectiveness
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
The solution effectively reduces laser-induced damage to the target material, enhances Xenon ice stability, and minimizes contamination, allowing for sustained operation and improved performance of the plasma-based light source.
Implementation Method 1
a target material is irradiated by an excitation source, such as a pulsed laser beam, in a vacuum chamber to produce plasma
Implementation Method 2
light having the desired wavelength is emitted by plasma formed from a target material having an appropriate line-emitting or band-emitting element
Data Source
AI summary
The present disclosure is directed to laser produced plasma light sources having a target material, such as Xenon, that is coated on the outer surface of a cylindrically-symmetric element (e.g., drum). Embodiments include a pre-pulsing arrangement which can be optimized to reduce irradiation damage to the drum and a pulse trimming unit which can be employed to reduce irradiation damage to the drum. In addition, an embodiment is disclosed wherein the surface of a cylindrically-symmetric element is formed with a plurality of grooves having a groove depth greater than 1 mm and a focusing unit focusing a laser beam and establishing an irradiation site to produce plasma from the target material, with the irradiation site distanced from a groove surface portion to protect the surface portion from irradiation damage.