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Focal plane position detection with a diffractive optic for shack-hartmann wave-front sensor fabrication
Applied Optics
|March 22, 2008
Summary
Accurate Shack-Hartmann sensor construction requires precise focal length determination. A novel method using off-axis lens segments achieves 12-mum rms error, improving wave-front measurement accuracy.
Area of Science:
- Optical engineering
- Wave-front sensing technology
Background:
- Accurate wave-front measurements are critical for Shack-Hartmann sensors.
- Determining the precise focal length, especially for large f/# lenses, is challenging due to minimal focal spot changes near the focal plane.
Purpose of the Study:
- To develop a reliable method for determining the focal plane location in Shack-Hartmann sensor construction.
- To overcome the limitations of traditional methods with large f/# lenses.
Main Methods:
- Utilized an array of off-axis lens segments.
- Analyzed transverse focal spot position variations on a CCD detector.
- Correlated spot displacement with axial position changes.
Main Results:
- Achieved a 12-mum root-mean-square (rms) error in axial position measurement.
- Successfully measured focal plane location while moving a 4-mm-focal-length optic over 1 mm.
Conclusions:
- The proposed method offers a precise and accurate way to determine focal plane location.
- This technique enhances the construction and performance of Shack-Hartmann wave-front sensors.
