Talbot assisted hexagonal beam patterning in a thin liquid crystal film with a single feedback mirror at negative distance

Ciaramella, E.; Tamburrini, M.; Santamato, Enrico

doi:10.1063/1.110735

Cited by 60 publications

(33 citation statements)

References 8 publications

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“…A combination of two lenses with focal distances f = 15 cm and separated by a distance of 2f = 30 cm creates a virtual image of a real mirror, placed at a distance d after the last lens, at a distance 2f − d before the first lens. This configuration has been used to study Talbot physics and even allows negative distances to be realized [26,27]. The m-CBS beam is reflected with an angle θ 0 ∼ 1…”

Section: Methodsmentioning

confidence: 99%

Coherent backscattering of inelastic photons from atoms and their mirror images

et al. 2016

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Coherent backscattering is a coherence effect in the propagation of waves through disordered media involving two or more scattering events. Here, we report on the observation of coherent backscattering from individual atoms and their mirror images. This system displays two important advantages: First, the effect can be observed at low optical densities, which allows to work in very dilute clouds or far from resonance. Second, due to the fact that the radiation of an atom interferes constructively with that of its own image, the phenomenon is much more robust to dephasing induced by strong saturation. In particular, the contribution of inelastically scattered photons to the interference process is demonstrated.

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Section: Methodsmentioning

confidence: 99%

Coherent backscattering of inelastic photons from atoms and their mirror images

et al. 2016

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“…Within paraxial approximation, any periodic spatial modulation with a transverse wavelength Λ will reproduce itself after the so-called Talbot distance, z T = 2Λ 2 /λ, where λ is the light wavelength. At a quarter of this distance a phase modulation is transferred into an amplitude modulation 27 giving the feedback distance, z T /4 = 2d, where optimal positive feedback occurs for a self-focusing medium (neglecting nonlinear absorption). This leads to a length scale of Λ ∝ √ 4dλ 25,26 .…”

Section: Methodsmentioning

confidence: 99%

“…The feedback mirror is located outside the vacuum chamber where the cold atoms are produced. We therefore use a telescope to image the mirror onto a plane located near the cold atomic cloud, producing a 'virtual mirror' whose distance to the sample can be adjusted from positive to negative values 27 . The typical saturation parameter range for the pump is between 0.05 and 1.…”

Section: Methodsmentioning

confidence: 99%

“…If this feedback is positive, its effect is to enhance the initial index fluctuations leading to the growth of a macroscopic transverse modulation of both light intensity and refractive index, and to the spontaneous appearance of patterns. The typical length scale Λ of the emerging pattern is set by diffraction and can be adjusted by varying the feedback distance [25][26][27] . The index of refraction of our cold atomic cloud can be written in the form…”

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confidence: 99%

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Optomechanical self-structuring in a cold atomic gas

et al. 2014

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The rapidly developing field of optomechanics aims at the com- bined control of optical and mechanical modes1–3. In cold atoms, the spontaneous emergence of spatial structures due to opto- mechanical back-action has been observed in one dimension in optical cavities3–8 or highly anisotropic samples9. Extensions to higher dimensions that aim to exploit multimode configurations have been suggested theoretically10–16. Here, we describe a simple experiment with many spatial degrees of freedom, in which two continuous symmetries—rotation and translation in the plane orthogonal to a pump beam axis—are spontaneously broken. We observe the simultaneous long- range spatial structuring (with hexagonal symmetry) of the density of a cold atomic cloud and of the pump optical field, with adjustable length scale. Being based on coherent phenom- ena (diffraction and the dipole force), this scheme can poten- tially be extended to quantum degenerate gases

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“…defocusing) if d > 0 (resp. d < 0) (Ciaramella et al, 1993). The transmitted backward beam B out is monitored by CCD cameras.…”

Section: Introductionmentioning

confidence: 99%

Experimental spatial rogue patterns in an optical feedback system

Odent

Taki

Louvergneaux

2010

Nat. Hazards Earth Syst. Sci.

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Abstract. We study pattern formation in an optical system composed of a Kerr medium subjected to optical feedback but in a regime very far from the modulational instability threshold. In this highly nonlinear regime, the dynamics is turbulent and the associated one-dimensional patterns depict rare and intense localized optical peaks. We analyse numerically and experimentally the statistics and features of these intense optical peaks and show that their probability density functions (PDF) have a long tail indicating the occurrence of rogue events.

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Talbot assisted hexagonal beam patterning in a thin liquid crystal film with a single feedback mirror at negative distance

Cited by 60 publications

References 8 publications

Coherent backscattering of inelastic photons from atoms and their mirror images

Coherent backscattering of inelastic photons from atoms and their mirror images

Optomechanical self-structuring in a cold atomic gas

Experimental spatial rogue patterns in an optical feedback system

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