Vortex structure of elongated speckles

Белый, В. Н.; Kazak, N. S.; Хило, Н. А.; Ропот, П. И.

doi:10.1117/12.751866

Cited by 5 publications

(4 citation statements)

References 6 publications

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“…This confirms the non-diffracting or non-diverging nature of the generated speckles. The speckles generated by the scattering of a ring-shaped scatterer can be represented by the linear superposition of BG beams which are known for their nondiffracting nature [21].…”

Section: Generation Of Non-diffracting Specklesmentioning

confidence: 99%

“…The generation and the evolution of random non-diffracting fields are getting a lot of attention in the recent years [17][18][19][20]. Recently, the quasi non-diffracting speckles have been generated using a ring-shaped scatterer and physical mechanism behind their formation has been explained [21]. We have studied this kind of random field and speckle generation for the optical vortex beam [22,23].…”

Section: Introductionmentioning

confidence: 99%

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Non-diffracting speckles of a perfect vortex beam

Reddy

Chithrabhanu

Vaity

et al. 2016

J. Opt.

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We generate perfect optical vortex (POV) beams, whose intensity distribution is independent of the order, and scatter them through a rough surface. We show that the size of produced speckles is independent of the order of the POV and their Fourier transform gives the random non-diffracting fields. The invariant size of speckles over the free space propagation verifies their non-diffracting or non-diverging nature. The size of speckles can be easily controlled by changing the axicon parameter, used to generate the Bessel–Gauss beams whose Fourier transform provides the POV. These results may be useful in applications of POV for authentication in cryptography.

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Section: Generation Of Non-diffracting Specklesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Non-diffracting speckles of a perfect vortex beam

Reddy

Chithrabhanu

Vaity

et al. 2016

J. Opt.

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“…The properties of such a non-diffracting speckle field have been studied in detail in many papers. 4,5 In this paper, following our recent work, 6 we will break down the equilibrium state and the diffraction invariant property of the non-diffracting speckle field by removing the continuous part of phase. An iterative procedure is introduced to efficiently eliminate most of optical vortices from a non-diffracting speckle field.…”

Section: Non-diffracting Speckle Fieldmentioning

confidence: 98%

Evolution of vortex density in a non-diffracting speckle field with its continuous phase removed

Chen

Dainty

2011

SPIE Proceedings

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We break down the equilibrium state and the diffraction invariant property of a non-diffracting speckle field by removing its continuous part of the phase while leaving all vortices behind. During the propagation of such a phase corrected non-diffracting speckle field, the vortex density drops down to a minimum value and then comes back to an equilibrium value which is even higher than the initial one. Before the phase corrected field returns back to its new equilibrium state, another least-squares phase removal will be applied, at the position where there is a minimum vortex density, to further remove vortices from the speckle field. Such a process of removing least-squares phase and propagating the phase corrected field over a distance can be repeated to eliminate most of optical vortices. Statistical results show that most of optical vortices can be removed from a non-diffracting speckle field. Finally, a semi-plane wave without optical vortices can be obtained from an initial non-diffracting speckle field with multiple steps of least-square phase correction.

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“…Particularly, bio-mimicry of desert beetle needs the elongated spindle like speckles. Though there are reported works on speckles with different aspect ratios, the spindle speckles were not realized till date [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Speckle lithography for fabricating biomimetic spindle structures of desert beetle skin

Bingi

Murukeshan

2017

Biomed. Phys. Eng. Express

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The desert beetle or namib beetle has inspired the scientific community for decades due to its water collecting, harvesting and frost control capabilities. The exact and robust bio-mimicry of this surface is challenging and essential for a better understanding of surface processes and to align them with the significant applications. This paper realizes the fabrication of such structures by a novel concept of integrating the shape engineered spindle speckles with photo-lithography. The uniformly shaped spindle speckle patterns are achieved using a 'diffuser-lens-aperture' optical configuration. It is demonstrated that the fabricated structures that mimic the desert beetle skin are exhibiting excellent super hydrophobic properties. The obtained results also indicate that these structures can be tailored for open air fluidic channels in lab-on-chip and clinical applications.

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Vortex structure of elongated speckles

Abstract: A novel type of quasi-nondiffracting (elongated) speckle fields having the vortex structure of individual speckles is investigated. A physical mechanism of forming the elongated vortex fields is established. Two optical schemes for forming such fields are proposed and realized.

Cited by 5 publications

References 6 publications

Non-diffracting speckles of a perfect vortex beam

Non-diffracting speckles of a perfect vortex beam

Evolution of vortex density in a non-diffracting speckle field with its continuous phase removed

Speckle lithography for fabricating biomimetic spindle structures of desert beetle skin

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