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1Faculty of Engineering, Niigata University, 8050 Ikarashi 2, Niigata-shi 950-2181, Japan. osami@eng.niigata-u.ac.jp
Applied Optics
|March 20, 2008
Summary
This study presents a novel method for measuring optical path length (OPL) using sinusoidal phase-modulating interferometry. The technique achieves high accuracy for OPL measurements exceeding a wavelength, crucial for advanced optical systems.
Area of Science:
- Optical Physics
- Interferometry
- Metrology
Background:
- Measuring optical path length (OPL) exceeding a wavelength presents challenges in interferometry.
- Conventional phase-based methods have limitations for large OPL values.
Purpose of the Study:
- To develop a high-accuracy method for measuring optical path length (OPL) larger than a wavelength.
- To improve the precision of interferometric measurements using sinusoidal phase modulation.
Main Methods:
- Utilized sinusoidal phase-modulating interferometry with a superluminescent laser diode.
- Employed sinusoidal wavelength scanning to achieve a large scanning width.
- Combined sinusoidal phase-modulation amplitude (Z(b)) with conventional phase values.
Main Results:
- Achieved measurement errors smaller than half the central wavelength.
- Demonstrated high-accuracy measurement of OPL over tens of micrometers with nanometer precision.
- Successfully measured large optical path differences using the developed interferometer.
Conclusions:
- The sinusoidal wavelength-scanning interferometer offers a robust solution for precise OPL measurement.
- This method enhances the capability of interferometry for applications requiring measurement of large optical path lengths.
- The technique provides a significant advancement in high-accuracy metrology for optical systems.
