Related Experiment Video
Updated: Jun 20, 2026

A Multimodal Wide-Field Fourier-Transform Raman Microscope
Published on: December 30, 2025
Group-delay measurement using the Fourier transform of an interferometric cross correlation generated by white light
Abstract:
A new method and apparatus for measuring the group delay in optical components and laser cavities are described. Cross-correlational fringes are fully recorded with a Michelson interferometer, in one of whose arms the optics to be measured are inserted. The path difference of the interferometer is calibrated to subwavelength accuracy, and the group delay is calculated from the phase of the Fourier transform of the measured fringe. The group delay for the entire visible-wavelength region is evaluated after a single measurement in approximately 10 min, using white light.
Related Concept Videos
Interference and Diffraction
Discrete-time Fourier transform
One of the notable...
Properties of Fourier Transform I
In radio broadcasting, multiple audio signals often need to be transmitted simultaneously. The Fourier...
Phase Contrast and Differential Interference Contrast Microscopy
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
Continuous -time Fourier Transform

