Annular Excimer Laser Cavity with Nested Brewster Windows
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Solution Overview
Problem
The benefits of deep gain saturation effect in excimer laser systems with a ring cavity structure are not fully utilized due to the physical constraints on reducing the length of the ring cavity, limiting amplification times and resulting in unstable laser output.
Innovation Solution
The excimer laser system incorporates a dual-electrode structure with two pairs of Brewster windows, positioning the annular optical path entirely within the power amplifier chamber to reduce the ring cavity length, increasing amplification times and achieving deeper gain saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the length of the ring cavity is reduced to increase amplification times, then the laser output stability is improved, but the physical space required for the cavity structure becomes constrained
Solution Approach 1:
The patent embeds the annular optical path structure entirely within the power amplifier chamber, nesting the optical components (mirrors, beam splitting system) inside the existing chamber volume. This allows the ring cavity to be compact without requiring additional external space, thereby increasing amplification times while maintaining a constrained physical footprint.
Solution Approach 2:
The patent transforms the traditional linear or external ring cavity configuration into a two-dimensional annular path that循环利用 the chamber volume. By arranging mirrors at 45° angles and creating a quadrilateral annular optical path, the system maximizes the optical path length within the available three-dimensional space, effectively increasing amplification times without proportionally increasing the chamber dimensions.
2Productivity
If the annular optical path is positioned entirely within the power amplifier chamber, then the amplification times are increased, but the device complexity increases
Solution Approach 1:
The patent combines the ring cavity structure with the power amplifier chamber into a single integrated unit. The annular optical path shares the same physical space as the amplification medium, eliminating the need for separate external cavity structures. This merging reduces the overall system complexity despite the sophisticated internal optical arrangement, as the optical components are housed within the existing chamber infrastructure.
Solution Approach 2:
The power amplifier chamber serves multiple functions: it houses the amplification medium, contains the annular optical path for multi-pass amplification, and provides the physical enclosure for the entire laser system. This multi-functionality reduces the need for additional separate components, thereby managing device complexity while achieving high amplification times through the integrated annular configuration.
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 enhances the stability and output characteristics of the excimer laser system by increasing amplification times and improving laser polarization, leading to a more stable and efficient power amplification mechanism.
Implementation Method 1
the amplification times N = c • Δt / L, wherein L indicates for the length of the ring cavity, c is the speed of light, and Δt indicates for the pulse width. The longer the L, the smaller the amplification times will be. Therefore, the amplification times N can be increased by reducing the length of the ring cavity, thereby obtaining a more stable laser output.
Implementation Method 2
the power amplifier chamber has a first pair of Brewster windows and a second pair of Brewster windows, wherein the first pair of Brewster windows is located in a first amplification optical path of the annular optical path along with a discharging electrode of the power amplifier chamber
Data Source
Figure 1
Figure 2~3
AI summary
The present disclosure provides an excimer laser system. A master oscillator chamber may generate laser pulses with a narrowed line width and a small energy by means of a line width narrowing module, as a seed light. The seed light is refracted by a master oscillator wavefront engineering box and then incident into a power amplifier chamber through a beam splitting system.The beam splitting system, a first high reflectance mirror, a second high reflectance mirror and a third high reflectance mirror may constitute a quadrilateral annular optical path, The power amplifier chamber may have a first pair of Brewster windows and a second pair of Brewster windows, wherein the first pair of Brewster windows is located in a first optical path of the annular optical path along with a discharging electrode of the power amplifier chamber, and the second pair of Brewster windows is located in a second optical path of annular optical path which is parallel to a first amplification optical path. The present disclosure reduces the length of a ring cavity of an excimer laser system with a ring cavity structure, increasing the amplification times and achieving a deeper gain saturation amplification than a traditional structure, thereby improving the output characteristic of the excimer laser system.