Related Experiment Video
Updated: Mar 11, 2026
11:08
Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
19.6K
Near-core structure of a propagating optical vortex.
Summary
This study reveals a consistent phase dip in optical vortex beams near the core, with spiraling phase contours. Both propagating and evanescent waves contribute to this phenomenon, offering new insights into vortex beam behavior.
Area of Science:
- Optics and Photonics
- Wave Propagation
- Vortex Beam Physics
Background:
- Optical vortex beams are characterized by helical wavefronts.
- The near-core region of vortex beams exhibits complex phase behavior.
- Previous explanations for near-core wavefronts involved evanescent fields or superoscillatory functions.
Purpose of the Study:
- To investigate the propagation of a charge-1 vortex beam.
- To elucidate the detailed wavefront structure in the near-core region.
- To analyze the contributions of different wave components to the observed phase behavior.
Main Methods:
- Utilized the angular spectrum method for analyzing vortex beam propagation.
- Incorporated both propagating and evanescent spatial frequencies.
- Examined the evolution of the wavefront structure over propagation distances.
Main Results:
- Observed a consistent and significant phase dip in the near-core region across all propagation distances.
- Phase contour lines in the near-core region were found to spiral around the beam core.
- The radial extent of the phase dip increased with propagation, while its magnitude remained constant.
Conclusions:
- Both propagating and evanescent components contribute to the observed near-core phase dip.
- The phase dip is attributed to the radial component of the propagation vector near the core.
- The angular spectrum method is a valuable tool for probing the intricate near-core structure of optical vortices.
More Related Videos
11:00Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section
Published on: July 19, 2016
12.0K
09:17Experimental Investigation of the Flow Structure over a Delta Wing Via Flow Visualization Methods
Published on: April 23, 2018
11.3K
Related Concept Videos
01:07Propagation of Waves
3.1K
When a wave propagates from one medium to another, part of it may get reflected in the first medium, and part of it may get transmitted to the second medium. In such a case, the interface of the two mediums can be considered as a boundary that is neither fixed nor free.
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
3.1K
01:30Propagation Speed of Electromagnetic Waves
4.9K
Electromagnetic waves are consistent with Ampere's law. Assuming there is no conduction current Ampere's law is given as:
4.9K
01:28Standing Waves in a Cavity
1.6K
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
1.6K
01:29Potential Due to a Polarized Object
879
A neutral atom consists of a positively charged nucleus surrounded by a negatively charged electron cloud. When placed in an external electric field, the external electric force pulls the electrons and nucleus apart, opposite to the intrinsic attraction between the nucleus and the electrons. The opposing forces balance each other with a slight shift between the center of masses of the nucleus and the electron cloud, resulting in a polarized atom. On the other hand, a few molecules, like water,...
879
01:28Irrotational Flow
1.1K
Irrotational flow is characterized by fluid motion where particles do not rotate around their axes, resulting in zero vorticity. For a flow to be irrotational, the curl of the velocity field must be zero. This imposes specific conditions on velocity gradients. For instance, to maintain zero rotation about the z-axis, the gradient condition:
1.1K
01:19The Structure of Intermediate Filaments
5.9K
The intermediate filaments are one of three widely studied cytoskeletal filaments. They are so named as their diameter (10 nm) is in between that of microfilaments (7 nm) and the microtubules (25 nm). These filaments are highly stable and can remain intact when exposed to high salt concentrations and detergents. These filaments are responsible for providing stability and mechanical support to the cells. They also help in cell adhesion and maintaining tissue integrity.
Intermediate...
Intermediate...
5.9K