Optical Material Laser Stability Evaluation via Fluorescence
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for evaluating optical materials for high-energy radiation applications are insufficient in distinguishing laser-stable materials from less stable ones, particularly due to high sensitivity requirements and lengthy testing processes, which lead to increased production costs and quality control issues in photolithography.
Innovation Solution
A method involving pre-irradiation with high-energy light followed by fluorescence measurements at different wavelengths, specifically using excitation wavelengths between 350-700 nm, with a waiting period to assess the formation of sodium-stabilized F centers, allowing for the differentiation of laser-stable and particularly laser-stable materials through fluorescence changes over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fluorescence measurement methods are used immediately after pre-irradiation, then the measurement process is fast, but the sensitivity is insufficient to distinguish laser-stable materials from less stable ones
Solution Approach 1:
The patent applies preliminary action by introducing a waiting period after pre-irradiation before performing the fluorescence measurement. This waiting period allows radiation damage and color center formation to develop fully, thereby increasing the sensitivity of the subsequent fluorescence measurement for distinguishing laser-stable materials. The measurement is performed after the material has been allowed to undergo its radiation response, rather than immediately after irradiation.
2Reliability
If long-term testing is performed to evaluate laser stability, then the reliability of material selection is high, but the productivity and production costs are reduced
Solution Approach 1:
The patent performs preliminary radiation damage evaluation by conducting pre-irradiation followed by a waiting period and fluorescence measurement. This preliminary test predicts long-term laser stability behavior without requiring actual long-term exposure testing. The fluorescence characteristics measured after the waiting period serve as indicators of how the material will perform under prolonged high-energy laser exposure, thereby providing reliable material selection in a short time frame.
Solution Approach 2:
The patent creates a simplified model of long-term radiation damage by using pre-irradiation followed by fluorescence measurement. Instead of performing actual long-term laser exposure tests, the method uses a shortened protocol that replicates the essential damage mechanisms (color center formation) and measures their effects through fluorescence. This copying approach provides reliable predictions of long-term stability without the time cost of actual long-term testing.
3Measurement precision
If high-energy laser pre-irradiation is used to induce fluorescence, then radiation damage is activated, but the intrinsic fluorescence signal is insufficient for quality control
Solution Approach 1:
The patent uses a second laser with a longer wavelength as an intermediary to measure the fluorescence signal. Instead of using the high-energy pre-irradiation laser (which causes radiation damage) for measurement, a different laser operating at a safer wavelength is employed to excite and measure the fluorescence. This intermediary approach allows the measurement of radiation-induced fluorescence without causing additional harmful radiation damage during the measurement process.
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
Enables the short-term evaluation of laser-stable materials by measuring fluorescence changes after pre-irradiation, reducing the need for lengthy testing and improving the quality control of optical materials for high-energy applications, such as DUV lithography and electronic device production.
Implementation Method 1
Through both intrinsic and non-intrinsic absorption, energy is deposited in the optical material, leading to its heating
Implementation Method 2
During rapid damage, part of the absorbed radiation is not only converted into heat, but is also re-emitted in the form of fluorescence
Implementation Method 3
A method is described for determining the laser stability of optical material by pre-irradiation with a laser and subsequent determination of the induced fluorescence
Data Source
Figure 1
Figure 2A~2B
Figure 3(a)~3(b)
AI summary
The method involves determining an induced non intrinsic fluorescence. The induced fluorescence directly activated after pre radiation and after 10 minutes after the end of the pre-radiation with light of a wavelength between 350-700 nanometers. The intensity of this fluorescence is determined between 550 and 810 nanometers and evaluated quantitatively with one or more wavelengths within the range.