Two-wavelength interferometry that uses a fourier-transform method.

Area of Science:

• Optics and Photonics
• Metrology
• Interferometry

Background:

• Two-wavelength interferometry is a technique used for precise measurements.
• Fourier-transform methods are commonly applied in interferometry for phase analysis.
• Phase errors can arise due to variations in modulation intensity between wavelengths.

Purpose of the Study:

• To investigate a Fourier-transform-based two-wavelength interferometry method.
• To analyze phase errors caused by intensity differences at two wavelengths.
• To develop a method for obtaining accurate phase maps in two-wavelength interferometry.

Main Methods:

• Utilized a Fourier-transform method for two-wavelength interferometry.
• Measured a phase profile at a synthetic wavelength from a two-wavelength interferogram.
• Employed two spatial carrier frequencies for phase retrieval.
• Theoretically and numerically analyzed phase errors.
• Developed a power-spectrum adjustment technique.

Main Results:

• Successfully measured a phase profile at a synthetic wavelength.
• Quantified the phase error resulting from differences in modulation intensities.
• Demonstrated that a phase map free of error can be obtained.
• Validated the effectiveness of the power-spectrum adjustment method.

Conclusions:

• The investigated Fourier-transform-based two-wavelength interferometry is effective.
• Phase errors in two-wavelength interferometry can be accurately analyzed and corrected.
• The power-spectrum adjustment method provides a robust solution for error compensation.
• This technique enables precise phase mapping with high accuracy.