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An optical vortex (also known as a photonic quantum vortex, screw dislocation or phase singularity) is a zero of an optical field; a point of zero intensity. The term is also used to describe a beam of light that has such a zero in it. The study of these phenomena is known as singular optics.
In the figure to the right, the first column shows the beam wavefront shape. The second column is the optical phase distribution in a beam cross-section, shown in false colors. The third column is the light intensity distribution in a beam cross-section (with a dark vortex core at the center).
Light, or more generally an electromagnetic wave, carries not only energy but also momentum, which is a characteristic property of all objects in translational motion. The existence of this momentum becomes apparent in the "radiation pressure " phenomenon, in which a light beam transfers its momentum to an absorbing or scattering object, generating a mechanical pressure on it in the process.
In contrast to the work of Bozinovic et al., which used a custom optical fiber that had a "vortex" refractive-index profile, the work by G. Milione et al. and H. Huang et al. showed that OAM multiplexing could be used in commercially available optical fibers by using digital MIMO post-processing to correct for mode mixing within the fiber. This ...
An optical vortex coronagraph uses a phase-mask in which the phase shift varies azimuthally around the center. Several varieties of optical vortex coronagraphs exist: the scalar optical vortex coronagraph based on a phase ramp directly etched in a dielectric material, like fused silica. [3] [4]
In a superfluid, a quantum vortex is a hole with the superfluid circulating around the vortex axis; the inside of the vortex may contain excited particles, air, vacuum, etc. The thickness of the vortex depends on a variety of factors; in liquid helium, the thickness is of the order of a few Angstroms.
Freezing weather is expected to hit the eastern US in the coming days as the polar vortex moves. Temperatures are expected to remain below average for the south-east and East Coast through the ...
This concept includes electrothermal vortex, electrophoresis, dielectrophoresis, and electroosmosis induced by combination of optical and electrical energy or by optical-electrical energy transfer. In 1995, an electrothermal vortices induced by a strong IR ( infrared ) laser projected into an electric field have been utilized to concentrate ...