Structural stability of spiral vortex beams to sector perturbations

Alexander Volyar; Yana Akimova

doi:10.1364/ao.435420

Structural stability of spiral beams and fine structure of an energy flow

Computer Optics ◽

10.18287/2412-6179-co-885 ◽

2021 ◽

Vol 45 (4) ◽

pp. 482-489

Author(s):

A.V. Volyar ◽

E.G. Abramochkin ◽

E.V. Razueva ◽

Ya.E. Akimova ◽

M.V. Bretsko

Keyword(s):

Structural Stability ◽

Critical Points ◽

Degrees Of Freedom ◽

Light Flux ◽

Special Role ◽

Quantum Numbers ◽

Energy Flows ◽

Spiral Vortex ◽

Vortex Beams ◽

Spiral Beam

The problem of structural stability of wave systems with great numbers of degrees of freedom directly concerns the issue of redistribution of energy fluxes in structured vortex beams that ensure their stability under propagating and focusing. A special place in this variety is occupied by spiral vortex beams capable of mapping complex figures, letters and even words. Spiral beams contain an infinite set of Laguerre-Gauss beams with a strong sequence of topological charges and radial numbers, their amplitudes and phases are tightly matched. Therefore, the problem of structural stability plays a special role for their applications. Using a combination of theory and computer simulation, supported by experiment, we ana-lyzed the structure of critical points in energy flows for two main types of spiral beams: triangular beams with zero radial number and triangular beams with complex framing of their faces with both quantum numbers. Structural stability is provided by triads of critical points, both inside and outside the triangle, which direct the light flux along the triangular generatrix and hold the framing when rotating the beam. The experiment showed that a simple triangular spiral beam turns out to be stable even with small alignment inaccuracies, whereas a complex triangular beam with a fram-ing requires careful alignment.

Download Full-text

Destroying and recovering spiral vortex beams due to figured perturbations

Journal of the Optical Society of America A ◽

10.1364/josaa.440756 ◽

2021 ◽

Author(s):

Alexander Volyar ◽

Eugeny Abramochkin ◽

Yana Akimova ◽

Mikhail Bretsko

Keyword(s):

Spiral Vortex ◽

Vortex Beams

Download Full-text

Structured Light and Darkness in Spiral Vortex Beams

10.1109/itnt52450.2021.9649131 ◽

2021 ◽

Author(s):

Alexander Volyar ◽

Evgeny Abramochkin ◽

Evgeniya Razueva ◽

Mihail Bretsko ◽

Yana Akimova ◽

...

Keyword(s):

Structured Light ◽

Spiral Vortex ◽

Vortex Beams

Download Full-text

Time-resolved high-resolution electron microscopy of structural stability in mgo clusters

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100165823 ◽

1996 ◽

Vol 54 ◽

pp. 672-673

Author(s):

T. Kizuka ◽

N. Tanaka

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Magnesium Oxide ◽

Structural Stability ◽

High Resolution Electron Microscopy ◽

Video Tape ◽

Solid State Physics ◽

Time Resolved ◽

Resolution Electron ◽

Structural And Functional Properties

Structure and stability of atomic clusters have been studied by time-resolved high-resolution electron microscopy (TRHREM). Typical examples are observations of structural fluctuation in gold (Au) clusters supported on silicon oxide films, graphtized carbon films and magnesium oxide (MgO) films. All the observations have been performed on the clusters consisted of single metal element. Structural stability of ceramics clusters, such as metal-oxide, metal-nitride and metal-carbide clusters, has not been observed by TRHREM although the clusters show anomalous structural and functional properties concerning to solid state physics and materials science.In the present study, the behavior of ceramic, magnesium oxide (MgO) clusters is for the first time observed by TRHREM at 1/60 s time resolution and at atomic resolution down to 0.2 nm.MgO and gold were subsequently deposited on sodium chloride (001) substrates. The specimens, single crystalline MgO films on which Au particles were dispersed were separated in distilled water and observed by using a 200-kV high-resolution electron microscope (JEOL, JEM2010) equipped with a high sensitive TV camera and a video tape recorder system.

Download Full-text