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SUMMARY:Propagation of beams with orbital angular momentum through 1D and 
 2D periodic grating (an analogue of the Talbot effect)
DTSTART;VALUE=DATE-TIME:20160705T090000Z
DTEND;VALUE=DATE-TIME:20160705T100000Z
DTSTAMP;VALUE=DATE-TIME:20260313T113648Z
UID:indico-contribution-1263@indico.inp.nsk.su
DESCRIPTION:Speakers: Oleg Kameshkov (Novosibirsk State University)\, Yuli
 a Choporova (Budker Institute of Nuclear Physics)\nTalbot effect (self-ima
 ging of periodic gratings) attracted attention for 170 years that have pas
 sed since its discovery. The invention of lasers generating coherent beams
  caused a new impetus to these studies. Commissioning of the Novosibirsk f
 ree electron laser facility\, which generates powerful coherent monochroma
 tic radiation in the terahertz range\, enabled us to demonstrate recently 
 the Talbot effect in this region of the spectrum. Large wavelength of the 
 terahertz radiation enables performing experiments with gratings\, fabrica
 ted using LIGA technology at synchrotron radiation source VEPP-4\, the str
 uctural elements of which are close to the wavelength. In this paper we de
 scribe first observation of diffraction patterns in the free space region 
 behind the periodic structures illuminated with beams carrying orbital ang
 ular momenta with topological charges equal to plus-minus 1 or 2. The imag
 es observed did not reproduce images of the gratings exactly\, but manifes
 ted some periodicity inherent to the Talbot effect with distorted spots re
 lated to individual grating openings. The numerical simulation of the elec
 tromagnetic field behind the gratings\, carried out in a frame of the Fres
 nel-Kirchhoff model\, is compared with the experimental data.\n\nhttps://i
 ndico.inp.nsk.su/event/3/contributions/1263/
LOCATION:Budker INP 2nd and 3rd floors
URL:https://indico.inp.nsk.su/event/3/contributions/1263/
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