Related Experiment Video
Updated: Jun 22, 2026

Femtosecond Laser Filaments for Use in Sub-Diffraction-Limited Imaging and Remote Sensing
Published on: April 25, 2019
White-light filaments induced by diffraction effects
Abstract:
The effect of beam spatial profile on self-focusing has been investigated. A circular aperture is used to create a Fresnel diffraction pattern. It is shown that self-focusing (a pre-requisite for filament formation) occurs in the presence of the aperture but that no formation is observed when the aperture is removed, even though the beam has higher power well above the threshold for critical power. An analytical solution to the Huygens-Fresnel diffraction integral shows that the axial intensity oscillates between maxima and minima as the distance from the aperture increases and that filament formation coincides with the presence of an axial maximum.
Related Concept Videos
Interference and Diffraction
X-ray Crystallography
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Formation of Intermediate Filaments
The de Broglie Wavelength
Super-resolution Fluorescence Microscopy
Determination of Crystal Structures

