Group-delay measurement using the Fourier transform of an interferometric cross correlation generated by white light

Area of Science:

• Optics and Photonics
• Interferometry
• Optical Metrology

Background:

• Accurate measurement of group delay is crucial for characterizing optical components and laser cavities.
• Existing methods may be time-consuming or lack precision across a broad spectral range.

Purpose of the Study:

• To introduce a new, rapid, and accurate method for measuring group delay in optical components and laser cavities.
• To enable comprehensive group delay evaluation across the visible spectrum.

Main Methods:

• Utilizing a Michelson interferometer to record cross-correlational fringes with the optical component in one arm.
• Calibrating the interferometer path difference to subwavelength accuracy.
• Calculating group delay from the phase of the Fourier transform of the fringe data.

Main Results:

• The method successfully measures group delay with high accuracy.
• Complete evaluation of group delay across the entire visible-wavelength region is achieved.
• Measurements are completed in approximately 10 minutes using white light.

Conclusions:

• The developed method offers a fast and precise approach for group delay characterization.
• This technique is suitable for evaluating optical components and laser cavities across the visible spectrum.