Stabilizing effect of random phase diffuser against wavefront distortions to the intensity distribution formed by Fourier hologram

2021 ◽  
Author(s):  
Andrii Derzhypolskyi ◽  
Oleksandr Gnatovskyi ◽  
Liudmyla Derzhypolska
Keyword(s):  
Intensity Distribution ◽  
Random Phase ◽  
Stabilizing Effect ◽  
Fourier Hologram

scholarly journals Topological stability of optical vortices diffracted by a random phase screen

2019 ◽  
Vol 43 (6) ◽  
pp. 917-925 ◽  
Author(s):  
V.V. Kotlyar ◽  
A.A. Kovalev ◽  
A.P. Porfirev
Keyword(s):  
Intensity Distribution ◽  
Topological Charge ◽  
Random Phase ◽  
Optical Vortex ◽  
Phase Screen ◽  
Optical Vortices ◽  
Average Intensity ◽  
Vortex Identification ◽  
Topological Stability ◽  
Random Phase Screen

Here, we theoretically demonstrate that if a Gaussian optical vortex is distorted by a random phase screen (diffuser) then the average intensity distribution in the focus of a spherical lens has a form of a ring with a nonzero value on the optical axis. The radius of the average-intensity ring depends on both the topological charge of an optical vortex and on the diffusing power of the diffuser. Therefore, the value of the topological charge cannot be unambiguously determined from the radius of the average intensity ring. However, the value of the topological charge of the optical vortex can be obtained from the number of points of phase singularity that can be determined using a Shack-Hartmann wavefront sensor. It is also shown that if we use a linear combination of two optical vortices, then the average intensity distribution has local maxima, the number of which is equal to the difference of the topological charges of the two original vortices. The number of these maxima no longer depends on the scattering force of the diffuser and can serve as an indicator for optical vortex identification. Modeling and experiments confirm the theoretical conclusions.

Structure images of Si, Ge and Mos2 crystals and some application to radiation damage studies

1978 ◽  
Vol 36 (1) ◽  
pp. 292-293 ◽  
Author(s):  
K. Izui ◽  
T. Nishida ◽  
S. Furuno ◽  
H. Otsu ◽  
S. Kuwabara
Keyword(s):  
Radiation Damage ◽  
Exposure Time ◽  
Gaussian Distribution ◽  
Intensity Distribution ◽  
Chromatic Aberration ◽  
Magnetic Lens

Recently we have observed the structure images of silicon in the (110), (111) and (100) projection respectively, and then examined the optimum defocus and thickness ranges for the formation of such images on the basis of calculations of image contrasts using the n-slice theory. The present paper reports the effects of a chromatic aberration and a slight misorientation on the images, and also presents some applications of structure images of Si, Ge and MoS2 to the radiation damage studies.(1) Effect of a chromatic aberration and slight misorientation: There is an inevitable fluctuation in the amount of defocus due to a chromatic aberration originating from the fluctuations both in the energies of electrons and in the magnetic lens current. The actual image is a results of superposition of those fluctuated images during the exposure time. Assuming the Gaussian distribution for defocus, Δf around the optimum defocus value Δf0, the intensity distribution, I(x,y) in the image formed by this fluctuation is given by

Étude de la formation de couches organiques auto assemblées à l'aide de la spectroscopie d'impédance électrochimique "odd random phase multisine"

2007 ◽  
Vol 95 ◽  
pp. 411-415
Author(s):  
T. Hauffman ◽  
J.-B. Jorcin ◽  
Y. V. Ingelgem ◽  
T. Breugelmans ◽  
E. Tourwe ◽  
...  
Keyword(s):  
Random Phase

Economical Pavement Design by Stabilizing Effect of Fly Ash and Lime

2012 ◽  
Vol 2 (3) ◽  
pp. 121-124
Author(s):  
Prof. N. R. Patil Prof. N. R. Patil ◽  
◽  
Prof. D. R. Kulkarni Prof. D. R. Kulkarni ◽  
Prof. S. D. Talegaonkar Prof. S. D. Talegaonkar
Keyword(s):  
Fly Ash ◽  
Pavement Design ◽  
Stabilizing Effect

The Stabilizing Effect of Pre-Equilibria: A Trifluoromethyl Complex as CF2 Reservoir in Catalytic Olefin Difluorocarbenation

2020 ◽  
Author(s):  
Thomas Louis-Goff ◽  
Huu Vinh Trinh ◽  
Eileen Chen ◽  
Arnold L. Rheingold ◽  
Christian Ehm ◽  
...  
Keyword(s):  
High Selectivity ◽  
Side Reactions ◽  
Theoretical Studies ◽  
Attractive Feature ◽  
Catalyst Recovery ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Experimental And Theoretical Studies

A new, efficient, catalytic difluorocarbenation of olefins to give 1,1-difluorocyclopropanes is presented. The catalyst, an organobismuth complex, uses TMSCF<sub>3</sub> as a stoichiometric difluorocarbene source. We demonstrate both the viability and robustness of this reaction over a wide range of alkenes and alkynes, including electron-poor alkenes, to generate the corresponding 1,1-difluorocyclopropanes and 1,1-difluorocyclopropenes. Ease of catalyst recovery from the reaction mixture is another attractive feature of this method. In depth experimental and theoretical studies showed that the key difluorocarbene-generating step proceeds through a bismuth non-redox synchronous mechanism generating a highly reactive free CF<sub>2</sub> in an endergonic pre-equilibrium. It is the reversibility when generating the difluorocarbene that accounts for the high selectivity, while minimizing CF<sub>2</sub>-recombination side-reactions.

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