Flanged Plasma Cell Using Fluoride Transmission Elements
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Solution Overview
Problem
Traditional plasma-based light sources using fused silica glass bulbs are limited by the absorption of short-wavelength radiation, leading to rapid degradation and potential explosion, which restricts the usefulness of laser-sustained plasma sources in the 190-260 nm range.
Innovation Solution
A plasma cell design featuring a transmission element made from materials like calcium fluoride, magnesium fluoride, crystalline quartz, or sapphire that is partially transparent to both pumping laser light and broadband radiation, including vacuum ultraviolet light, allowing for the generation and emission of short-wavelength radiation without causing degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fused silica glass bulbs are used in traditional plasma-based light sources, then the bulb structure is simple and easy to manufacture, but the bulb absorbs short-wavelength radiation (wavelengths shorter than approximately 190 nm) causing rapid degradation and potential explosion
Solution Approach 1:
The patent changes the material parameter of the transmission element from fused silica glass to materials with different optical properties (calcium fluoride, magnesium fluoride, crystalline quartz, or sapphire) that are transparent to short-wavelength radiation including vacuum ultraviolet wavelengths below 190 nm, thereby resolving the absorption issue while maintaining structural integrity
Solution Approach 2:
The patent employs composite construction by combining the transmission element made from short-wavelength transparent materials with flanged structures and mounting mechanisms, creating a composite assembly that maintains both optical transparency and mechanical stability in the plasma cell environment
2Ease of manufacture
If traditional fused silica glass bulbs are used, then manufacturing is simple, but the optical transmission capabilities degrade rapidly in spectral ranges including 190-260 nm
Solution Approach 1:
The patent changes the material composition parameter from fused silica glass to alternative materials (calcium fluoride, magnesium fluoride, crystalline quartz, or sapphire) that inherently possess transparency to vacuum ultraviolet radiation, thereby extending the operational duration without sacrificing manufacturing feasibility
3Device complexity
If fused silica glass is used in plasma bulbs, then the structure is straightforward, but overheating and explosion occur due to absorption of short-wavelength light
Solution Approach 1:
The patent changes the thermal and optical parameters of the transmission element by selecting materials with superior thermal conductivity and short-wavelength transparency (such as sapphire and crystalline quartz), which can dissipate heat more effectively and resist thermal degradation, thereby preventing overheating and explosion while maintaining structural simplicity
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 plasma cell effectively generates and transmits broadband radiation, including vacuum ultraviolet radiation, while preventing damage to the transmission element, thus extending the operational range of laser-sustained plasma sources beyond the limitations of traditional fused silica glass bulbs.
Implementation Method 1
Laser-sustained light sources operate by focusing laser radiation into a gas volume in order to excite the gas, such as argon or xenon, into a plasma state, which is capable of emitting light. This effect is typically referred to as 'pumping' the plasma.
Implementation Method 2
the plasma emits broadband radiation including at least vacuum ultraviolet radiation
Implementation Method 3
the transmission element of the plasma cell is at least partially transparent to at least a portion of the illumination generated by the illumination source and at least a portion of the vacuum ultraviolet radiation emitted by the plasma
Data Source
AI summary
A system for forming a light-sustained plasma capable of emitting vacuum ultraviolet light includes an illumination source configured to generate illumination, a plasma cell including a transmission element having one or more openings, one or more flanges disposed at the openings of the transmission element and configured to enclose the internal volume of the transmission element in order to contain a volume of gas within the plasma cell. The system further includes a collector element arranged to focus the illumination from the illumination source into the volume of gas to generate a plasma within the volume of gas contained within the plasma cell. Further, the plasma emits broadband radiation including at least vacuum ultraviolet radiation. In addition, the transmission element of the plasma cell is transparent to the illumination generated by the illumination source and at least the vacuum ultraviolet radiation emitted by the plasma.