Related Experiment Video
Updated: Jun 22, 2026

The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry
Published on: August 12, 2013
Anomalous phenomenon of a focused evanescent Laguerre-Gaussian beam
Abstract:
We demonstrate theoretically and experimentally an anomaly in the intensity distribution at the focal region of a Laguerre-Gaussian beam, when such a beam is focused by a high numerical aperture objective lens through an index-mismatched interface satisfying the total internal reflection condition. An asymmetric rotation of the focal field arising from the interplay of the phase shift induced by the total internal reflection and the helical phase of the Laguerre-Gaussian beam has been experimentally observed by a scanning near-field optical microscope. A cross-section analysis shows that the experimental results match well with the theoretical predictions.
Related Concept Videos
Interference and Diffraction
The de Broglie Wavelength
Focusing of Light in the Eye
Plane Electromagnetic Waves I
The EM field is assumed to be a...
Gauss's Law: Spherical Symmetry
Deflection of a Beam
Singularity functions, described in an earlier lesson, are powerful mathematical tools that represent discontinuities within a function commonly encountered in structural loading...

