137 research outputs found
Using the Scale Software for Critical Analysis
This article shows the experience of using the SCALE software package (hereinafter SCALE) to analyze the criticality of critical benchmark experiments.Β This experience was obtained during the familiarization of SCALE for research purposes on the basis of the Department of Nuclear Physics and Technologies (DNPaT) of the IATE MEPhI. Test calculations of the effective multiplication factor ( ) critical assemblies with different parameters was produced, research different method of calculate multigroup constants
Vortex-free laser beam with an orbital angular momentum
We show that if one cylindrical lens is placed in the Gaussian beam waist and another cylindrical lens is placed at some distance from the first one and rotated by some angle, then the laser beam after the second lens has an orbital angular momentum (OAM). An explicit analytical expression for the OAM of such a beam is obtained. Depending on the inter-lens distance, the OAM can be positive, negative, or zero. Such a laser beam has no isolated intensity nulls with a singular phase and it is not an optical vortex, but has an OAM. By choosing the radius of the beam waist of the source Gaussian beam, the focal lengths of the lenses and the distance between them, it is possible to generate a vortex-free laser beam equivalent to an optical vortex with a topological charge of several hundreds.This work was funded by the Russian Science Foundation grant # 17-19-0118
Controlling the orbital angular momentum of Gaussian vortices by shifting the point of phase singularity
A simple formula is obtained to describe the normalized orbital angular momentum (OAM) of a Gaussian beam after passing through a shifter spiral phase plate (SPP). The formula shows that while being equal to the topological charge at the zero off-axis shift, the OAM becomes fractional with increasing shift and it is tending to zero exponentially. Analytic expressions of the complex amplitude of the Gaussian beam having passed through the off-axis SPP show that as the beam propagates, the isolated intensity null moves from the initial point defined by the vector of the SPP's center shift along a straight line perpendicular to the said vector. Using a liquid crystal light modulator, crescent-shaped beams are experimentally generated.This work was supported by the Federal Agency of Scientific Organizations (agreement No 007-ΠΠ/Π§3363/26) and funded by the Russian Science Foundation (RSF), grant No. 17-19-01186
Measurements of spin rotation parameter A in pion-proton elastic scattering at 1.62 GeV/c
The ITEP-PNPI collaboration presents the results of the measurements of the
spin rotation parameter A in the elastic scattering of positive and negative
pions on protons at P_beam = 1.62 GeV/c. The setup included a
longitudinally-polarized proton target with superconductive magnet, multiwire
spark chambers and a carbon polarimeter with thick filter. Results are compared
to the predictions of partial wave analyses. The experiment was performed at
the ITEP proton synchrotron, Moscow.Comment: 7 pages, 3 figures. To be published in Phys. Lett.
Topological charge of a superposition of two Bessel-Gaussian beams
Π ΡΠ°Π±ΠΎΡΠ΅ ΡΠ΅ΠΎΡΠ΅ΡΠΈΡΠ΅ΡΠΊΠΈ ΠΏΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ Ρ ΡΡΠΏΠ΅ΡΠΏΠΎΠ·ΠΈΡΠΈΠΈ Π΄Π²ΡΡ
ΠΏΡΡΠΊΠΎΠ² ΠΠ΅ΡΡΠ΅Π»ΡβΠΠ°ΡΡΡΠ° Ρ ΡΠ°Π·Π½ΡΠΌΠΈ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ Π·Π°ΡΡΠ΄Π°ΠΌΠΈ ΠΈ ΡΠ°Π·Π½ΡΠΌΠΈ ΠΌΠ°ΡΡΡΠ°Π±Π½ΡΠΌΠΈ ΠΌΠ½ΠΎΠΆΠΈΡΠ΅Π»ΡΠΌΠΈ (ΡΠ°Π΄ΠΈΠ°Π»ΡΠ½ΡΠΌΠΈ ΠΏΡΠΎΠ΅ΠΊΡΠΈΡΠΌΠΈ Π²ΠΎΠ»Π½ΠΎΠ²ΡΡ
Π²Π΅ΠΊΡΠΎΡΠΎΠ²) ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ Π·Π°ΡΡΠ΄ ΡΠ°Π²Π΅Π½ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΌΡ Π·Π°ΡΡΠ΄Ρ ΡΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ° ΠΠ΅ΡΡΠ΅Π»ΡβΠΠ°ΡΡΡΠ°, Ρ ΠΊΠΎΡΠΎΡΠΎΠ³ΠΎ Π±ΠΎΠ»ΡΡΠ΅ ΠΌΠ°ΡΡΡΠ°Π±Π½ΡΠΉ ΠΌΠ½ΠΎΠΆΠΈΡΠ΅Π»Ρ. ΠΡΠ»ΠΈ Ρ ΠΏΡΡΠΊΠΎΠ² ΠΠ΅ΡΡΠ΅Π»ΡβΠΠ°ΡΡΡΠ° ΠΌΠ°ΡΡΡΠ°Π±Π½ΡΠ΅ ΠΌΠ½ΠΎΠΆΠΈΡΠ΅Π»ΠΈ ΡΠ°Π²Π½Ρ, ΡΠΎ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ Π·Π°ΡΡΠ΄ ΡΡΠΏΠ΅ΡΠΏΠΎΠ·ΠΈΡΠΈΠΈ ΡΠ°Π²Π΅Π½ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΌΡ Π·Π°ΡΡΠ΄Ρ ΡΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ° ΠΠ΅ΡΡΠ΅Π»ΡβΠΠ°ΡΡΡΠ°, Ρ ΠΊΠΎΡΠΎΡΠΎΠ³ΠΎ Π±ΠΎΠ»ΡΡΠ΅ ΠΌΠΎΠ΄ΡΠ»Ρ Π²Π΅ΡΠΎΠ²ΠΎΠ³ΠΎ ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΠ° (Π±ΠΎΠ»ΡΡΠ΅ ΠΌΠΎΡΠ½ΠΎΡΡΡ). ΠΡΠ»ΠΈ ΠΈ ΠΌΠΎΡΠ½ΠΎΡΡΠΈ ΠΏΡΡΠΊΠΎΠ² ΠΎΠ΄ΠΈΠ½Π°ΠΊΠΎΠ²Ρ, ΡΠΎ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ Π·Π°ΡΡΠ΄ ΡΡΠΏΠ΅ΡΠΏΠΎΠ·ΠΈΡΠΈΠΈ ΡΠ°Π²Π΅Π½ ΡΡΠ΅Π΄Π½Π΅ΠΌΡ Π°ΡΠΈΡΠΌΠ΅ΡΠΈΡΠ΅ΡΠΊΠΎΠΌΡ ΠΎΡ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
Π·Π°ΡΡΠ΄ΠΎΠ² ΠΊΠ°ΠΆΠ΄ΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ° ΠΠ΅ΡΡΠ΅Π»ΡβΠΠ°ΡΡΡΠ° Π² ΡΡΠΏΠ΅ΡΠΏΠΎΠ·ΠΈΡΠΈΠΈ. ΠΡΠΈ ΡΡΠ»ΠΎΠ²ΠΈΠΈ, ΡΡΠΎ ΡΡΠΌΠΌΠ° ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
Π·Π°ΡΡΠ΄ΠΎΠ² ΠΎΠ±ΠΎΠΈΡ
ΠΏΡΡΠΊΠΎΠ² Π½Π΅ΡΡΡΠ½Π°Ρ, ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ Π·Π°ΡΡΠ΄ ΡΡΠΏΠ΅ΡΠΏΠΎΠ·ΠΈΡΠΈΠΈ Π±ΡΠ΄Π΅Ρ ΠΏΠΎΠ»ΡΡΠ΅Π»ΡΠΌ ΡΠΈΡΠ»ΠΎΠΌ. ΠΠΎ Π½Π° ΠΏΡΠ°ΠΊΡΠΈΠΊΠ΅ ΠΈΠ·-Π·Π° ΠΊΠΎΠ½Π΅ΡΠ½ΠΎΠ³ΠΎ ΡΠ°Π΄ΠΈΡΡΠ° ΠΎΠΊΡΡΠΆΠ½ΠΎΡΡΠΈ, Π½Π° ΠΊΠΎΡΠΎΡΠΎΠΌ ΡΠ°ΡΡΡΠΈΡΡΠ²Π°Π΅ΡΡΡ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ Π·Π°ΡΡΠ΄, ΠΏΠΎΠ»ΡΡΠ΅Π»ΠΎΠ³ΠΎ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π·Π°ΡΡΠ΄Π° Π΄Π»Ρ Π²ΡΡΠΎΠΆΠ΄Π΅Π½Π½ΠΎΠ³ΠΎ ΡΠ»ΡΡΠ°Ρ Π½Π΅ ΠΏΠΎΠ»ΡΡΠ°Π΅ΡΡΡ. ΠΠΌΠ΅ΡΡΠΎ ΠΏΠΎΠ»ΡΡΠ΅Π»ΠΎΠ³ΠΎ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π·Π°ΡΡΠ΄Π°, ΠΏΠΎΠ»ΡΡΠ°Π΅ΡΡΡ ΡΠ΅Π»ΡΠΉ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ Π·Π°ΡΡΠ΄, ΠΌΠ΅Π½ΡΡΠΈΠΉ ΠΈΠ· Π΄Π²ΡΡ
. ΠΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΏΠΎΠΊΠ°Π·ΡΠ²Π°Π΅Ρ, ΡΡΠΎ ΠΏΡΠΈ Π½Π΅Π±ΠΎΠ»ΡΡΠΎΠΉ ΡΠ°Π·Π½ΠΈΡΠ΅ Π² Π²Π΅ΡΠΎΠ²ΡΡ
ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΠ°Ρ
ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ Π·Π°ΡΡΠ΄ ΡΡΠΏΠ΅ΡΠΏΠΎΠ·ΠΈΡΠΈΠΈ Π½Π΅ ΡΠΎΡ
ΡΠ°Π½ΡΠ΅ΡΡΡ: Π² Π±Π»ΠΈΠΆΠ½Π΅ΠΉ Π·ΠΎΠ½Π΅ ΠΈ Π·ΠΎΠ½Π΅ Π€ΡΠ΅Π½Π΅Π»Ρ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ Π·Π°ΡΡΠ΄ ΡΠ°Π²Π΅Π½ Π±ΠΎΠ»ΡΡΠ΅ΠΌΡ ΠΈΠ· Π΄Π²ΡΡ
, Π° Π² Π΄Π°Π»ΡΠ½Π΅ΠΉ Π·ΠΎΠ½Π΅ β ΠΌΠ΅Π½ΡΡΠ΅ΠΌΡ. ΠΡΠΈΡΠ΅ΠΌ ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π·Π°ΡΡΠ΄Π° ΠΎΡ Π±ΠΎΠ»ΡΡΠ΅Π³ΠΎ ΠΊ ΠΌΠ΅Π½ΡΡΠ΅ΠΌΡ ΠΏΡΠΎΠΈΡΡ
ΠΎΠ΄ΠΈΡ Π½Π΅ ΡΠΊΠ°ΡΠΊΠΎΠΌ, Π° Π½Π΅ΠΏΡΠ΅ΡΡΠ²Π½ΠΎ Π½Π° Π½Π΅ΠΊΠΎΡΠΎΡΠΎΠΌ ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΠΈ. Π ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄Π½ΠΎΠΉ Π·ΠΎΠ½Π΅ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ Π·Π°ΡΡΠ΄ Π΄ΡΠΎΠ±Π½ΡΠΉ.
Here we show theoretically that a superposition of two Bessel-Gaussian (BG) beams with different topological charges (TC) and different scaling factors (radial components of the wave vectors) has the TC equal to that of the BG beam with the larger scaling factor. If the scaling factors of the BG beams are equal, then TC of the whole superposition equals TC of the BG beam with the larger (in absolute value) weight coefficient in the superposition (i.e. with larger power). If the constituent BG beams are also same-power, TC of the superposition equals the average TC of the two BG beams. Therefore, if the sum of TCs of both beams is odd, TC of the superposition is a half-integer number. In practice, however, TC is calculated over a finite radius circle and, hence, the half-integer TC for the degenerated case cannot be obtained. Instead of the half-integer TC, the lower of the two integer TCs is obtained. Numerical simulation reveals that if the weight coefficients in the superposition are slightly different, TC of the superposition is not conserved on propagation. In the near field and in the Fresnel diffraction zone, TC is equal to the highest TC of the two BG beams, while in the far field it is equal to the lower TC. What is more, TC changes its value from high to low not instantly, but continuously at some propagation distance. In the intermediate zone TC is fractional.Π Π°Π±ΠΎΡΠ° Π²ΡΠΏΠΎΠ»Π½Π΅Π½Π° ΠΏΡΠΈ ΠΏΠΎΠ΄Π΄Π΅ΡΠΆΠΊΠ΅ Π ΠΎΡΡΠΈΠΉΡΠΊΠΎΠ³ΠΎ ΡΠΎΠ½Π΄Π° ΡΡΠ½Π΄Π°ΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ (Π³ΡΠ°Π½Ρ 18-29-20003 Π² ΡΠ°ΡΡΡΡ
Β«Π Π°ΡΡΠ΅Ρ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π·Π°ΡΡΠ΄Π° ΡΡΠΌΠΌΡ Π΄Π²ΡΡ
ΠΏΡΡΠΊΠΎΠ² ΠΠΒ» ΠΈ Β«Π’ΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΉ Π·Π°ΡΡΠ΄ ΡΡΠΏΠ΅ΡΠΏΠΎΠ·ΠΈΡΠΈΠΈ Π΄Π²ΡΡ
ΠΏΡΡΠΊΠΎΠ² ΠΠ΅ΡΡΠ΅Π»ΡβΠΠ°ΡΡΡΠ° Ρ ΠΎΠ΄ΠΈΠ½Π°ΠΊΠΎΠ²ΡΠΌΠΈ Π²Π΅ΡΠΎΠ²ΡΠΌΠΈ ΠΈ ΠΌΠ°ΡΡΡΠ°Π±Π½ΡΠΌΠΈ ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΠ°ΠΌΠΈΒ»), Π ΠΎΡΡΠΈΠΉΡΠΊΠΎΠ³ΠΎ Π½Π°ΡΡΠ½ΠΎΠ³ΠΎ ΡΠΎΠ½Π΄Π° (Π³ΡΠ°Π½Ρ 18-19-00595 Π² ΡΠ°ΡΡΡΡ
Β«ΠΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅Β» ΠΈ Β«ΠΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ Π² ΡΠ»ΡΡΠ°Π΅ ΠΏΡΠΈΠΌΠ΅ΡΠ½ΠΎΠ³ΠΎ ΡΠ°Π²Π΅Π½ΡΡΠ²Π° Π²Π΅ΡΠΎΠ²ΡΡ
ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΠΎΠ²Β»), Π° ΡΠ°ΠΊΠΆΠ΅ ΠΠΈΠ½ΠΈΡΡΠ΅ΡΡΡΠ²Π° Π½Π°ΡΠΊΠΈ ΠΈ Π²ΡΡΡΠ΅Π³ΠΎ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΡ Π Π€ Π² ΡΠ°ΠΌΠΊΠ°Ρ
Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΈΡ ΡΠ°Π±ΠΎΡ ΠΏΠΎ ΠΠΎΡΡΠ΄Π°ΡΡΡΠ²Π΅Π½Π½ΠΎΠΌΡ Π·Π°Π΄Π°Π½ΠΈΡ Π€ΠΠΠ¦ Β«ΠΡΠΈΡΡΠ°Π»Π»ΠΎΠ³ΡΠ°ΡΠΈΡ ΠΈ ΡΠΎΡΠΎΠ½ΠΈΠΊΠ°Β» Π ΠΠ Π² ΡΠ°ΡΡΠΈ Β«ΠΠ²Π΅Π΄Π΅Π½ΠΈΠ΅Β» ΠΈ Β«ΠΠ°ΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅Β»
Membranes with a boundary
We investigate the recently developed theory of multiple membranes. In
particular, we consider open membranes, i.e. the theory defined on a membrane
world volume with a boundary. We first restrict our attention to the gauge
sector of the theory. We obtain a boundary action from the Chern-Simons terms.
Secondly, we consider the addition of certain boundary terms to various
Chern-Simons theories coupled to matter. These terms ensure the full bulk plus
boundary action has the correct amount of supersymmetry. For the ABJM model,
this construction motivates the inclusion of a boundary quartic scalar
potential. The boundary dynamics obtained from our modified theory produce
Basu-Harvey type equations describing membranes ending on a fivebrane. The
ultimate goal of this work is to throw light on the theory of fivebranes using
the theory of open membranes.Comment: 48 pages, Latex, v2 references adde
Transformation of a high-order edge dislocation to optical vortices (spiral dislocations)
Π’Π΅ΠΎΡΠ΅ΡΠΈΡΠ΅ΡΠΊΠΈ ΠΏΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ Π°ΡΡΠΈΠ³ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ΅ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΊΡΠ°Π΅Π²ΠΎΠΉ Π΄ΠΈΡΠ»ΠΎΠΊΠ°ΡΠΈΠΈ (ΠΏΡΡΠΌΠΎΠΉ Π»ΠΈΠ½ΠΈΠΈ Π½ΡΠ»Π΅Π²ΠΎΠΉ ΠΈΠ½ΡΠ΅Π½ΡΠΈΠ²Π½ΠΎΡΡΠΈ) n-Π³ΠΎ ΠΏΠΎΡΡΠ΄ΠΊΠ° ΡΠΎΡΠΌΠΈΡΡΠ΅Ρ Π½Π° Π΄Π²ΠΎΠΉΠ½ΠΎΠΌ ΡΠΎΠΊΡΡΠ½ΠΎΠΌ ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΠΈ ΠΎΡ ΡΠΈΠ»ΠΈΠ½Π΄ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π»ΠΈΠ½Π·Ρ n ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠ»Π»ΠΈΠΏΡΠΈΡΠ΅ΡΠΊΠΈΡ
Π²ΠΈΡ
ΡΠ΅ΠΉ (Π²ΠΈΠ½ΡΠΎΠ²ΡΡ
Π΄ΠΈΡΠ»ΠΎΠΊΠ°ΡΠΈΠΉ) Ρ Π΅Π΄ΠΈΠ½ΠΈΡΠ½ΡΠΌ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΌ Π·Π°ΡΡΠ΄ΠΎΠΌ, ΡΠ°ΡΠΏΠΎΠ»ΠΎΠΆΠ΅Π½Π½ΡΡ
Π½Π° ΠΏΡΡΠΌΠΎΠΉ Π»ΠΈΠ½ΠΈΠΈ, ΠΏΠ΅ΡΠΏΠ΅Π½Π΄ΠΈΠΊΡΠ»ΡΡΠ½ΠΎΠΉ ΠΊΡΠ°Π΅Π²ΠΎΠΉ Π΄ΠΈΡΠ»ΠΎΠΊΠ°ΡΠΈΠΈ, Π² ΡΠΎΡΠΊΠ°Ρ
, ΠΊΠΎΠΎΡΠ΄ΠΈΠ½Π°ΡΡ ΠΊΠΎΡΠΎΡΡΡ
ΡΠ²Π»ΡΡΡΡΡ ΠΊΠΎΡΠ½ΡΠΌΠΈ ΠΌΠ½ΠΎΠ³ΠΎΡΠ»Π΅Π½Π° ΠΡΠΌΠΈΡΠ° n-Π³ΠΎ ΠΏΠΎΡΡΠ΄ΠΊΠ°. ΠΡΠ±ΠΈΡΠ°Π»ΡΠ½ΡΠΉ ΡΠ³Π»ΠΎΠ²ΠΎΠΉ ΠΌΠΎΠΌΠ΅Π½Ρ ΠΊΡΠ°Π΅Π²ΠΎΠΉ Π΄ΠΈΡΠ»ΠΎΠΊΠ°ΡΠΈΠΈ Ρ Π°ΡΡΠΈΠ³ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠ°Π·ΠΎΠΉ ΠΏΡΠΎΠΏΠΎΡΡΠΈΠΎΠ½Π°Π»Π΅Π½ n.
We theoretically show that an astigmatic transformation of an nth-order edge dislocation (a zero-intensity straight line) produces n optical elliptical vortices (spiral dislocations) with unit topological charge at the double focal distance from the cylindrical lens, located on a straight line perpendicular to the edge dislocation, at points whose coordinates are the roots of an nth-order Hermite polynomial. The orbital angular momentum of the edge dislocation is proportional to the order n.Π Π°Π±ΠΎΡΠ° Π²ΡΠΏΠΎΠ»Π½Π΅Π½Π° ΠΏΡΠΈ ΠΏΠΎΠ΄Π΄Π΅ΡΠΆΠΊΠ΅ Π ΠΎΡΡΠΈΠΉΡΠΊΠΎΠ³ΠΎ ΡΠΎΠ½Π΄Π° ΡΡΠ½Π΄Π°ΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ (Π³ΡΠ°Π½Ρ 18-29-20003, ΠΏΠ°ΡΠ°Π³ΡΠ°Ρ Β«ΠΠΎΠΌΠΏΠ»Π΅ΠΊΡΠ½Π°Ρ Π°ΠΌΠΏΠ»ΠΈΡΡΠ΄Π° ΠΏΠΎΠ»Ρ Ρ ΠΊΡΠ°Π΅Π²ΠΎΠΉ Π΄ΠΈΡΠ»ΠΎΠΊΠ°ΡΠΈΠ΅ΠΉ Π½Π° Π΄Π²ΠΎΠΉΠ½ΠΎΠΌ ΡΠΎΠΊΡΡΠ½ΠΎΠΌ ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΠΈΒ»), Π ΠΎΡΡΠΈΠΉΡΠΊΠΎΠ³ΠΎ Π½Π°ΡΡΠ½ΠΎΠ³ΠΎ ΡΠΎΠ½Π΄Π° (Π³ΡΠ°Π½Ρ 18-19-00595, ΠΏΠ°ΡΠ°Π³ΡΠ°Ρ Β«ΠΡΠ±ΠΈΡΠ°Π»ΡΠ½ΡΠΉ ΡΠ³Π»ΠΎΠ²ΠΎΠΉ ΠΌΠΎΠΌΠ΅Π½ΡΒ»), Π° ΡΠ°ΠΊΠΆΠ΅ ΠΠΈΠ½ΠΈΡΡΠ΅ΡΡΡΠ²Π° Π½Π°ΡΠΊΠΈ ΠΈ Π²ΡΡΡΠ΅Π³ΠΎ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΡ Π Π€ Π² ΡΠ°ΠΌΠΊΠ°Ρ
Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΈΡ ΡΠ°Π±ΠΎΡ ΠΏΠΎ ΠΠΎΡΡΠ΄Π°ΡΡΡΠ²Π΅Π½Π½ΠΎΠΌΡ Π·Π°Π΄Π°Π½ΠΈΡ Π€ΠΠΠ¦ Β«ΠΡΠΈΡΡΠ°Π»Π»ΠΎΠ³ΡΠ°ΡΠΈΡ ΠΈ ΡΠΎΡΠΎΠ½ΠΈΠΊΠ°Β» Π ΠΠ (ΠΏΠ°ΡΠ°Π³ΡΠ°Ρ Β«ΠΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅Β»)
Experimental investigation of the energy backflow in the tight focal spot
Π‘ ΠΏΠΎΠΌΠΎΡΡΡ Π΄Π²ΡΡ
ΠΎΠ΄ΠΈΠ½Π°ΠΊΠΎΠ²ΡΡ
ΠΌΠΈΠΊΡΠΎΠΎΠ±ΡΠ΅ΠΊΡΠΈΠ²ΠΎΠ² Ρ ΡΠΈΡΠ»ΠΎΠ²ΠΎΠΉ Π°ΠΏΠ΅ΡΡΡΡΠΎΠΉ 0,95 Π±ΡΠ»ΠΎ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΠΎ ΠΏΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΠΈΠ½ΡΠ΅Π½ΡΠΈΠ²Π½ΠΎΡΡΡ Π½Π° ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΎΡΠΈ Π² ΠΏΠ»ΠΎΡΠΊΠΎΡΡΠΈ ΡΠΎΠΊΡΡΠ° ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π²ΠΈΡ
ΡΡ Ρ ΡΠΎΠΏΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΌ Π·Π°ΡΡΠ΄ΠΎΠΌ 2 ΡΠ°Π²Π½Π° Π½ΡΠ»Ρ Π΄Π»Ρ ΡΠ²Π΅ΡΠ° Ρ ΠΏΡΠ°Π²ΠΎΠΉ ΠΊΡΡΠ³ΠΎΠ²ΠΎΠΉ ΠΏΠΎΠ»ΡΡΠΈΠ·Π°ΡΠΈΠ΅ΠΉ ΠΈ Π½Π΅Π½ΡΠ»Π΅Π²Π°Ρ Π΄Π»Ρ ΡΠ²Π΅ΡΠ° Ρ Π»Π΅Π²ΠΎΠΉ ΠΊΡΡΠ³ΠΎΠ²ΠΎΠΉ ΠΏΠΎΠ»ΡΡΠΈΠ·Π°ΡΠΈΠ΅ΠΉ. ΠΠΎΠ΄ΡΠ²Π΅ΡΠΆΠ΄Π΅Π½ΠΈΠ΅ΠΌ ΡΠΎΠ³ΠΎ, ΡΡΠΎ Π² ΠΏΠΎΡΠ»Π΅Π΄Π½Π΅ΠΌ ΡΠ»ΡΡΠ°Π΅ Π½Π° ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΎΡΠΈ ΡΡΡΠ΅ΡΡΠ²ΡΠ΅Ρ ΠΎΠ±ΡΠ°ΡΠ½ΡΠΉ ΠΏΠΎΡΠΎΠΊ ΡΠ½Π΅ΡΠ³ΠΈΠΈ, ΡΠ²Π»ΡΠ΅ΡΡΡ Π½Π°Π»ΠΈΡΠΈΠ΅ Π² ΡΠ΅Π½ΡΡΠ΅ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½Π½ΠΎΠ³ΠΎ ΠΏΠΎΡΠΎΠΊΠ° ΡΠ½Π΅ΡΠ³ΠΈΠΈ ΡΠ»Π°Π±ΠΎΠ³ΠΎ Π»ΠΎΠΊΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΌΠ°ΠΊΡΠΈΠΌΡΠΌΠ° (ΠΏΡΡΠ½Π° ΠΡΠ°Π³ΠΎ), ΠΎΠ±ΡΡΡΠ½ΡΠ΅ΠΌΠΎΠ³ΠΎ Π΄ΠΈΡΡΠ°ΠΊΡΠΈΠ΅ΠΉ ΠΏΡΡΠΌΠΎΠ³ΠΎ ΠΏΠΎΡΠΎΠΊΠ° ΡΠ½Π΅ΡΠ³ΠΈΠΈ Π½Π° ΠΊΡΡΠ³Π΅ Π΄ΠΈΠ°ΠΌΠ΅ΡΡΠΎΠΌ 300 Π½ΠΌ (ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΡΠ΅Ρ Π΄ΠΈΠ°ΠΌΠ΅ΡΡΡ ΡΡΡΠ±ΠΊΠΈ ΠΎΠ±ΡΠ°ΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΡΠΎΠΊΠ° ΡΠ½Π΅ΡΠ³ΠΈΠΈ). Π‘ΡΠ°Π²Π½ΠΈΠ²Π°Ρ ΡΠΈΡΠ»Π΅Π½Π½ΡΠ΅ ΠΈ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΠ΅ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΈΠ½ΡΠ΅Π½ΡΠΈΠ²Π½ΠΎΡΡΠΈ, Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΠΈΡΡ Π΄ΠΈΠ°ΠΌΠ΅ΡΡ ΡΡΡΠ±ΠΊΠΈ ΠΎΠ±ΡΠ°ΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΡΠΎΠΊΠ° β ΠΎΠ½ ΡΠ°Π²Π΅Π½ ΡΠ°ΡΡΡΠΎΡΠ½ΠΈΡ ΠΌΠ΅ΠΆΠ΄Ρ Π½ΡΠ»ΡΠΌΠΈ ΠΈΠ½ΡΠ΅Π½ΡΠΈΠ²Π½ΠΎΡΡΠΈ. ΠΠ»Ρ ΡΠΈΡΠ»ΠΎΠ²ΠΎΠΉ Π°ΠΏΠ΅ΡΡΡΡΡ 0,95 ΠΈ Π΄Π»ΠΈΠ½Ρ Π²ΠΎΠ»Π½Ρ 532 Π½ΠΌ Π΄ΠΈΠ°ΠΌΠ΅ΡΡ ΡΡΡΠ±ΠΊΠΈ ΠΎΠ±ΡΠ°ΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΡΠΎΠΊΠ° ΡΠ°Π²Π΅Π½ 300 Π½ΠΌ. Π’Π°ΠΊΠΆΠ΅ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΠΎ ΠΏΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΠΏΡΠΈ ΡΠΎΠΊΡΡΠΈΡΠΎΠ²ΠΊΠ΅ ΡΠΈΠ»ΠΈΠ½Π΄ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π²Π΅ΠΊΡΠΎΡΠ½ΠΎΠ³ΠΎ ΠΏΡΡΠΊΠ° Π²ΡΠΎΡΠΎΠ³ΠΎ ΠΏΠΎΡΡΠ΄ΠΊΠ° Π»ΠΈΠ½Π·ΠΎΠΉ Ρ ΡΠΈΡΠ»ΠΎΠ²ΠΎΠΉ Π°ΠΏΠ΅ΡΡΡΡΠΎΠΉ 0,95 Π²ΠΎΠ·Π½ΠΈΠΊΠ°Π΅Ρ ΠΎΡΠ΅ΡΠΈΠΌΠΌΠ΅ΡΡΠΈΡΠ½ΡΠΉ ΠΏΠΎΡΠΎΠΊ ΡΠ½Π΅ΡΠ³ΠΈΠΈ Ρ ΠΎΡΠ΅Π½Ρ ΡΠ»Π°Π±ΡΠΌ ΠΌΠ°ΠΊΡΠΈΠΌΡΠΌΠΎΠΌ Π² ΡΠ΅Π½ΡΡΠ΅ (ΠΏΡΡΠ½ΠΎ ΠΡΠ°Π³ΠΎ). Π’Π°ΠΊΠΎΠ΅ ΡΠ°ΡΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΠΎΠ±ΡΡΡΠ½ΡΠ΅ΡΡΡ Π΄ΠΈΡΡΠ°ΠΊΡΠΈΠ΅ΠΉ ΠΏΡΡΠΌΠΎΠ³ΠΎ ΠΏΠΎΡΠΎΠΊΠ° ΡΠ½Π΅ΡΠ³ΠΈΠΈ Π½Π° ΠΊΡΡΠ³Π»ΠΎΠΉ ΠΎΠ±Π»Π°ΡΡΠΈ Π΄ΠΈΠ°ΠΌΠ΅ΡΡΠΎΠΌ 300 Π½ΠΌ, Π² ΠΊΠΎΡΠΎΡΠΎΠΉ ΠΏΠΎΡΠΎΠΊ ΡΠ½Π΅ΡΠ³ΠΈΠΈ ΠΎΠ±ΡΠ°ΡΠ½ΡΠΉ. ΠΡΠΎ ΡΠ°ΠΊΠΆΠ΅ ΡΠ²Π»ΡΠ΅ΡΡΡ ΠΏΠΎΠ΄ΡΠ²Π΅ΡΠΆΠ΄Π΅Π½ΠΈΠ΅ΠΌ ΠΏΡΠΈΡΡΡΡΡΠ²ΠΈΡ ΠΎΠ±ΡΠ°ΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΡΠΎΠΊΠ° ΡΠ½Π΅ΡΠ³ΠΈΠΈ Π½Π° ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΎΡΠΈ.
Using two identical microobjectives with a numerical aperture NA = 0.95, we experimentally demonstrate that the on-axis intensity near the tight focal spot of an optical vortex with a topological charge 2 is zero for right-handed circular polarization and nonzero for left-handed circular polarization. This serves to confirm that in the latter case there is a reverse energy flow on the optical axis, as testified by a very weak local maximum (the Arago spot) detected at the center of the measured energy flow distribution, caused by diffraction of the direct energy flow by a 300 nm circle (the diameter of a reverse energy flow tube). The comparison of numerical and experimental intensity distributions shows that it is possible to determine the diameter of the reverse energy flow "tube", which is equal to the distance between the adjacent intensity nulls. For NA = 0.95 and a 532 nm incident wavelength, the diameter of the on-axis reverse energy flow "tube" is measured to be 300 nm. It is also experimentally shown that when an optical beam with second-order cylindrical polarization is focused with a lens with NA = 0.95, there is a circularly symmetric energy flow in the focus with a very weak maximum in the center (the Arago spot), whose distribution is determined by diffraction of the direct energy flow by a 300 nm circular region, where the energy flow is reverse. This also confirms that in this case, there is a reverse energy flow on the optical axis.Π Π°Π±ΠΎΡΠ° Π²ΡΠΏΠΎΠ»Π½Π΅Π½Π° ΠΏΡΠΈ ΠΏΠΎΠ΄Π΄Π΅ΡΠΆΠΊΠ΅ Π ΠΎΡΡΠΈΠΉΡΠΊΠΎΠ³ΠΎ Π½Π°ΡΡΠ½ΠΎΠ³ΠΎ ΡΠΎΠ½Π΄Π° (Π³ΡΠ°Π½Ρ 18-19-00595) Π² ΡΠ°ΡΡΠΈ Β«ΠΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½Ρ ΠΏΠΎ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ ΠΎΠ±ΡΠ°ΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΡΠΎΠΊΠ° Π² ΡΠΎΠΊΡΡΠ΅ ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ Π²ΠΈΡ
ΡΡ Ρ ΠΊΡΡΠ³ΠΎΠ²ΠΎΠΉ ΠΏΠΎΠ»ΡΡΠΈΠ·Π°ΡΠΈΠ΅ΠΉΒ», Π ΠΎΡΡΠΈΠΉΡΠΊΠΎΠ³ΠΎ ΡΠΎΠ½Π΄Π° ΡΡΠ½Π΄Π°ΠΌΠ΅Π½ΡΠ°Π»ΡΠ½ΡΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ (Π³ΡΠ°Π½Ρ 18-29-20003) Π² ΡΠ°ΡΡΠΈ Β«ΠΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½Ρ ΠΏΠΎ ΠΎΠ±Π½Π°ΡΡΠΆΠ΅Π½ΠΈΡ ΠΎΠ±ΡΠ°ΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΡΠΎΠΊΠ° Π² ΡΠΎΠΊΡΡΠ΅ ΠΏΠΎΠ»ΡΡΠΈΠ·Π°ΡΠΈΠΎΠ½Π½ΠΎΠ³ΠΎ Π²ΠΈΡ
ΡΡ Π²ΡΠΎΡΠΎΠ³ΠΎ ΠΏΠΎΡΡΠ΄ΠΊΠ°Β» ΠΈ ΠΠΈΠ½ΠΈΡΡΠ΅ΡΡΡΠ²Π° Π½Π°ΡΠΊΠΈ ΠΈ Π²ΡΡΡΠ΅Π³ΠΎ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°Π½ΠΈΡ Π Π€ Π² ΡΠ°ΠΌΠΊΠ°Ρ
Π²ΡΠΏΠΎΠ»Π½Π΅Π½ΠΈΡ ΡΠ°Π±ΠΎΡ ΠΏΠΎ ΠΠΎΡΡΠ΄Π°ΡΡΡΠ²Π΅Π½Π½ΠΎΠΌΡ Π·Π°Π΄Π°Π½ΠΈΡ Π€ΠΠΠ¦ Β«ΠΡΠΈΡΡΠ°Π»Π»ΠΎΠ³ΡΠ°ΡΠΈΡ ΠΈ ΡΠΎΡΠΎΠ½ΠΈΠΊΠ°Β» Π ΠΠ (ΡΠΎΠ³Π»Π°ΡΠ΅Π½ΠΈΠ΅ 007-ΠΠ/Π§3363/26) Π² ΡΠ°ΡΡΠΈ Β«Π‘ΠΈΠ»Ρ, Π΄Π΅ΠΉΡΡΠ²ΡΡΡΠΈΠ΅ Π½Π° Π½Π°Π½ΠΎΡΠ°ΡΡΠΈΡΡ Π² ΠΎΠ±ΡΠ°ΡΠ½ΠΎΠΌ ΠΏΠΎΡΠΎΠΊΠ΅ ΡΠ½Π΅ΡΠ³ΠΈΠΈΒ»
Orbital angular momentum of structurally stable laser beams
For structurally stable laser beams whose amplitude can be represented as a finite sum of the Hermite-Gaussian functions with undefined weight coefficients, we obtain an analytical expression for the normalized orbital angular momentum (OAM) that is also expressed through finite sums of weight coefficients. It is shown that a certain choice of weight coefficients allows obtaining the maximal OAM, which is equal to the maximal index of the Hermite polynomial in the sum. In this case, the sum describes a single-ringed Laguerre-Gaussian beam with a topological charge equal to the maximal OAM and to the maximal order of the Hermite polynomial
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