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Improvement of absolute accuracy for a multiple bounce reflectometer through a detailed effort to reduce systematic
Applied Optics
|February 4, 2010
Summary
This study significantly reduced systematic errors in multiple-bounce reflectometry for high-reflectivity mirrors. Enhanced accuracy to 0.001 was achieved through detailed component analysis and improved detection methods.
Area of Science:
- Optical physics
- Metrology
- Instrumentation
Background:
- Multiple-bounce reflectometry is crucial for precise optical measurements.
- Existing reflectometers face systematic errors, particularly with high-reflectivity mirrors.
- Previous measurements showed discrepancies with established standards.
Purpose of the Study:
- To construct and refine a multiple-bounce reflectometer.
- To significantly reduce systematic errors in reflectivity measurements.
- To improve the absolute accuracy and precision of the instrument.
Main Methods:
- Developed a multiple-bounce reflectometer based on Kelsall's design.
- Utilized computer programs to analyze Fresnel diffraction from apertures.
- Studied and minimized systematic errors associated with concave spherical mirror measurements.
- Investigated pathlength changes due to multiple bounces using computational analysis.
- Replaced the thermopile detector with a thin-film bolometer.
Main Results:
- Achieved absolute accuracy of 0.001 for reflectivity measurements.
- Demonstrated a precision of 0.0003.
- Significantly reduced systematic errors compared to previous methods.
- Corrected for discrepancies observed in prior measurements.
Conclusions:
- The refined multiple-bounce reflectometer offers superior accuracy for high-reflectivity mirrors.
- The implemented improvements address key sources of systematic error.
- This work advances the precision of optical reflectivity measurements.
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