Spectral interferometry and reflectometry used for characterization of a multilayer mirror

Area of Science:

• Optics and Photonics
• Materials Science
• Metrology

Background:

• Multilayer mirrors are crucial optical components.
• Accurate characterization of their spectral phase and group delay is essential for performance.
• Existing methods may lack precision or efficiency.

Purpose of the Study:

• To develop and demonstrate a white-light spectral interferometric technique.
• To retrieve the relative spectral phase and group delay of multilayer mirrors.
• To characterize multilayer mirrors using reflectance spectrum measurements.

Main Methods:

• Utilized a dispersive Michelson interferometer.
• Recorded spectral interferograms using white-light interferometry.
• Employed a windowed Fourier transform in the wavelength domain for phase retrieval.
• Performed a three-step measurement of the mirror's reflectance spectrum.

Main Results:

• Successfully retrieved the relative spectral phase of the multilayer mirror.
• Determined the group delay of the multilayer mirror.
• Obtained the reflectance spectrum of the multilayer mirror.

Conclusions:

• The developed white-light spectral interferometric technique provides accurate characterization of multilayer mirrors.
• The method effectively retrieves spectral phase and group delay.
• This technique offers a robust approach for optical component metrology.