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12:14
The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry
Published on: August 12, 2013
Experimental requirement of the error-compensating five-frame interferogram-collecting sequence used in
1Department of Chemical Engineering, Auburn University, 212 Ross Hall, Auburn University, Auburn, Alabama 36849, USA. ansarna@auburn.edu
Optics Letters
|January 26, 2011
Summary
Digital phase-shifting interferometry (PSI) height profile accuracy can be compromised by phase-step errors. A commonly used five-frame PSI sequence, while easy to execute, is less effective at reducing these errors compared to Hariharan
Area of Science:
- Optical Metrology
- Interferometry
- Surface Profilometry
Background:
- Digital phase-shifting interferometry (PSI) is crucial for optical testing, relying on precise phase steps between collected interferograms.
- Phase-step errors in PSI can significantly impact the accuracy of derived height profiles.
- The five-frame interferogram-collecting sequence proposed by Hariharan et al. is known for its effectiveness in mitigating these errors.
Purpose of the Study:
- To evaluate the effectiveness of a commonly used five-frame PSI sequence in reducing height profile errors.
- To compare the error-reduction capabilities of this sequence with the Hariharan et al. method.
- To highlight the trade-offs between ease of execution and accuracy in PSI data acquisition.
Main Methods:
- Analysis of a specific class of five-frame interferogram sequences.
- Mathematical comparison with the Hariharan et al. five-frame sequence.
- Evaluation of error propagation in height profile reconstruction.
Main Results:
- The commonly used five-frame sequence, despite its mathematical equivalence to Hariharan's method, demonstrates significantly reduced effectiveness in mitigating phase-step errors.
- Height profile errors are more pronounced when using the commonly employed sequence.
- Ease of execution does not guarantee superior accuracy in PSI.
Conclusions:
- The choice of a five-frame PSI sequence impacts the accuracy of height profile measurements.
- The Hariharan et al. sequence offers superior error reduction for PSI, despite potential complexities in execution.
- Practitioners should carefully consider the trade-offs between sequence simplicity and measurement fidelity in optical testing.
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