Deep ultraviolet laser source
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Solution Overview
Problem
Existing UV light sources for disinfection and sterilization, such as UV lamps and UV-LEDs, face limitations in power density, lifetime, and material compatibility issues, which restrict their effectiveness and safety in disinfecting large areas and maintaining operational longevity.
Innovation Solution
A deep ultraviolet (DUV) laser system utilizing a fiber laser source and nonlinear crystal assembly with compensation plates to generate laser pulses of less than 400 femtoseconds, achieving a fifth harmonic wavelength of 200-230 nm with high power density and extended longevity by optimizing spatial and temporal overlap of laser beams using birefringent materials like LBO for compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If UV lamps or UV-LEDs are used for disinfection, then the light source can kill microorganisms, but the power density is significantly smaller with distance from the source, requiring the source to be closer to the area of disinfection
Solution Approach 1:
The patent changes the wavelength parameter from conventional UV (254 nm) to deep ultraviolet (200-230 nm) range, which has shorter penetration length and higher absorption by biological tissues, thereby achieving effective disinfection at greater distances while maintaining safety. This parameter change enables the laser beam to propagate efficiently through large distances to affect pathogens at surfaces and volumes that are tens or hundreds of meters away from the laser source.
2Reliability
If UV lamps or UV-LEDs are used for disinfection, then the light source can kill pathogens, but these sources have a very short lifetime, resulting in continuous replacement of the UV lamp or LED
Solution Approach 1:
The patent replaces the mechanical/electrical UV lamp or LED system with a laser-based system. Lasers have no filaments, no phosphor coatings, and no electrical contacts that degrade, giving them significantly longer operational lifetimes. The laser source can be scanned at high speed to supply the appropriate power density to destroy the pathogens, and when proper laser design is implemented, laser sources have become more rugged with associated longer life expectancies.
3Productivity
If conventional UV light sources are used, then disinfection can be achieved, but there is a need for containing the spread of viruses using continuous non-chemical disinfection instead of discreet disinfection
Solution Approach 1:
The patent enables continuous disinfection action through the laser system. The laser can operate continuously and be scanned at high speed to cover large areas, providing ongoing disinfection rather than periodic treatment. This continuous operation capability allows for maintaining virus-free environments in real-time, which is essential for containing the spread of viruses in public spaces.
4Duration of action of stationary object
If DUV laser sources are used to achieve long operational life, then laser propagation efficiency is improved, but extraordinary precautions have to be taken into consideration, including the materials used near the laser light for purposes of avoiding damage to components
Solution Approach 1:
The patent employs inert atmosphere techniques by implementing continuous purging with gases such as dry air, nitrogen, argon, or helium to create a protective environment around the laser components. This inert atmosphere prevents oxidation and degradation of optical components exposed to the intense DUV laser light, thereby extending operational life while managing the complexity of material selection through environmental control rather than restrictive material specifications.
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 system provides efficient, long-lasting DUV laser light capable of disinfecting and sterilizing over large distances with high power density, improving applications like disinfection, sterilization, eye surgery, and micromachining, while minimizing material degradation and optical damage.
Implementation Method 1
a nonlinear crystal assembly comprising first, second, and third nonlinear crystals and configured to convert the fundamental laser beam to produce a fifth harmonic laser beam having a wavelength in a range from 200 nanometers (nm) to 230 nm
Implementation Method 2
at least one compensation plate disposed in at least one position preceding at least one of the first, second, and third nonlinear crystals and configured such that a pair of pulsed laser beams transmitted through the at least one compensation plate are spatially and temporally overlapped within the at least one of the first, second, and third nonlinear crystals
Data Source
AI summary
A method and system for generating deep ultraviolet (DUV) laser light is disclosed, in one embodiment the DUV laser system includes a fiber laser source configured to emit a poised fundamental laser beam in the near-infrared with a pulse duration of less than 400 femtoseconds (fs), a nonlinear crystal assembly comprising first, second, and third nonlinear crystals that is configured to convert the fundamental laser beam to produce a fifth harmonic laser beam having a wavelength in a range from 200 nanometers (nm) to 230 nm, and at least one compensation plate disposed in at least one position preceding at least one of the first, second, and third nonlinear crystals and configured such that a pair of pulsed laser beams transmitted through the at least one compensation plate are spatially and temporally overlapped within the at least one of the first, second, and third nonlinear crystals.