EUV Laser Master Oscillator Wavelength Matching
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Solution Overview
Problem
The use of CO2 gas lasers as master oscillators in EUV light source apparatuses complicates controller structures and handling, and it is challenging to generate light with wavelengths matching the amplifiable lines of molecular gas lasers using disparate laser apparatuses like solid lasers combined with nonlinear crystals.
Innovation Solution
A laser apparatus with a master oscillator outputting longitudinal-mode laser lights and an amplifier using molecular gas as an amplifying agent, where the wavelength of the laser light is adjusted to match the amplifiable lines of the amplifier, facilitated by a controller that adjusts the resonator length and wavelength selection elements like gratings and etalons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If CO2 gas lasers are used as master oscillators in EUV light source apparatuses, then amplification capability is improved, but controller structure complexity increases and handling becomes difficult
Solution Approach 1:
A wavelength selection element (etalon or grating) is introduced as an intermediary component between the CO2 gas laser master oscillator and the amplifier. This element mediates the wavelength matching process, enabling the complex CO2 gas laser system to output light at wavelengths that precisely match the amplifier's amplifiable lines, thereby resolving the contradiction between maintaining amplification capability and reducing controller complexity.
Solution Approach 2:
The invention changes the wavelength parameter of the master oscillator output by using a wavelength selection element. The etalon or grating selectively transmits or diffracts specific wavelength components, transforming the broad spectral output of the CO2 gas laser into a narrowband output that matches the amplifier's gain profile, thus simplifying the overall system control while maintaining high amplification efficiency.
2Adaptability or versatility
If disparate laser apparatuses like solid lasers combined with nonlinear crystals are used to generate light, then wavelength flexibility is improved, but difficulty in generating light at specific amplifiable lines increases
Solution Approach 1:
The wavelength selection element acts as an intermediary that bridges the gap between the broad wavelength flexibility of disparate laser sources and the specific wavelength requirements of the amplifier. It selectively extracts the desired wavelength components from the laser output, making it easier to generate light at specific amplifiable lines while maintaining wavelength flexibility.
Solution Approach 2:
The invention replaces complex mechanical wavelength tuning mechanisms with an optical wavelength selection element. Instead of mechanically adjusting cavity lengths or using complex feedback systems, the etalon or grating provides passive, stable wavelength selection based on optical interference or diffraction principles, thereby reducing the difficulty of generating light at specific wavelengths.
3Measurement precision
If wavelength selection elements like gratings and etalons are introduced, then wavelength matching precision is improved, but device complexity increases
Solution Approach 1:
The wavelength selection element serves as a compact intermediary component that achieves high wavelength matching precision through passive optical mechanisms. The etalon uses multiple-beam interference to provide narrow transmission bands, while the grating uses diffraction to separate wavelengths spatially. These elements achieve precise wavelength selection without requiring complex active control systems, thus improving wavelength matching while adding minimal device complexity.
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 configuration simplifies the handling of the master oscillator and enhances amplification efficiency by ensuring the laser light wavelength aligns with the amplifiable lines, improving the overall performance of the EUV light source apparatus.
Implementation Method 1
a master oscillator outputting one or more longitudinal-mode laser lights
Implementation Method 2
an amplifier with a molecular gas as an amplifying agency amplifying a longitudinal-mode laser light
Implementation Method 3
wavelength selection elements like gratings and etalons
Implementation Method 4
wavelength selection elements like gratings and etalons
Data Source
AI summary
An extreme ultraviolet light source apparatus comprises a laser apparatus having a master oscillator outputting one or more longitudinal-mode-laser lights, an amplifier with a molecular gas as an amplifying agency amplifying a longitudinal-mode laser light of which wavelength is included in one of amplifiable lines, and a controller adjusting the master oscillator so that the wavelength of the longitudinal-mode laser light outputted from the master oscillator is included in one of the amplifiable lines, the laser apparatus being used as a driver laser, wherein the laser apparatus irradiates a target material with a laser light for generating plasma, and the extreme ultraviolet light is emitted from the plasma and outputted from the extreme ultraviolet light source apparatus.