Electrode-Free Plasma Light Source with Dual-Mode Laser Ignition
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Solution Overview
Problem
Existing high-brightness continuous optical discharge (COD) light sources face challenges in reliable ignition and stability due to electrode-related disturbances, complex design, and inefficient laser power usage, with current solutions either being impractical or unreliable.
Innovation Solution
A solid-state laser system with a single active element generates two pulsed laser beams, one in free running and one in Q-switched mode, for plasma ignition and sustenance, using a CW laser with focused beams to maintain plasma without electrodes, simplifying the design and increasing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodes are used for plasma ignition, then plasma ignition is achieved, 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 of the harmful electrode component eliminates convective disturbances while maintaining plasma ignition capability through optical means.
Solution Approach 2:
The patent replaces the mechanical/electrical electrode system with an optical laser system for both plasma ignition and sustenance. The laser beam focuses energy to create and maintain plasma without physical contact, substituting mechanical electrode-discharge interaction with optical energy deposition.
2Reliability
If electrodes are positioned near plasma region, then plasma ignition is enabled, but radiation collection efficiency deteriorates due to dead spatial angles
Solution Approach 1:
By removing electrodes from the chamber, the patent eliminates the dead spatial angles they create. The laser system can focus energy precisely at the desired plasma location without the physical obstruction of electrodes blocking radiation pathways.
3Reliability
If high power laser is used for both plasma ignition and COD sustenance, then plasma ignition is achieved, but energy efficiency deteriorates due to excessive power consumption
Solution Approach 1:
The patent segments the laser operation into two distinct phases: a high-power pulsed phase for plasma ignition, and a low-power continuous phase for COD sustenance. This temporal and power-level segmentation allows the system to use high power only when necessary for ignition, then maintain plasma with minimal power.
Solution Approach 2:
The patent employs periodic high-power laser pulses for plasma ignition followed by continuous low-power operation for sustenance. This periodic high-power/low-power cycle achieves reliable ignition while minimizing overall energy consumption during the sustained plasma phase.
4Illumination intensity
If sharp focusing of laser beam is used, then brightness is improved, but device complexity increases due to precise alignment requirements
Solution Approach 1:
The patent uses a single laser system that performs multiple functions: plasma ignition, COD sustenance, and brightness generation. This multi-functionality reduces the need for separate alignment systems for different purposes, simplifying the overall device despite the need for sharp focusing.
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 enables the creation of high-brightness, stable broadband light sources with improved spatial and energy stability, reducing electrode-related disturbances and optimizing plasma radiation collection, while using lower laser power for sustained plasma.
Implementation Method 1
one in free running and one in Q-switched mode, for plasma ignition
Implementation Method 2
a region of radiating plasma sustained in the chamber by a focused beam of a continuous wave (CW) laser
Data Source
AI summary
The light source contains a gas-filled chamber with a plasma sustained by a focused beam of a continuous wave laser. The means for plasma ignition is a solid-state laser system which generates two pulsed laser beams: in a free running mode and in a Q-switched mode. The solid-state laser system contains single active element and its optical cavity is equipped with a Q-switch overlapping only part of a cross section of the intracavity laser beam. One pulsed laser beam provides an optical breakdown after which another pulsed laser beam ignites the plasma, the volume and density of which are sufficient for stationary sustenance of the plasma by the focused beam of the continuous wave laser. EFFECT: simplification of the design of the light source, increase of its reliability and ease of use, creating on this basis of powerful electrode-free high-brightness broadband light sources with high spatial and energy stability.