Enhanced optical pulse broadening in free-space optical links due to the radiative effects of atmospheric aerosols

Sunilkumar, K.; Anand, N.; Satheesh, S. K.; Moorthy, K. Krishna; Ilavazhagan, G.

doi:10.1364/oe.409794

Cited by 10 publications

(4 citation statements)

References 27 publications

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“…Hence, for the rest of this paper, we use the V as a measure of coherence. In freespace channels, decoherence mechanism such as dispersion and atmospheric turbulence could lead to a degradation of V. However, in our case, turbulence has been taken care of by the imaging (field-widened) interferometers, while for our laser pulse-width of 300 ps, dispersion is negligible 40,41 .…”

Section: Results Experimentsmentioning

confidence: 85%

Observing quantum coherence from photons scattered in free-space

Sajeed

Jennewein

2021

Light Sci Appl

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Quantum channels in free-space, an essential prerequisite for fundamental tests of quantum mechanics and quantum technologies in open space, have so far been based on direct line-of-sight because the predominant approaches for photon-encoding, including polarization and spatial modes, are not compatible with randomly scattered photons. Here we demonstrate a novel approach to transfer and recover quantum coherence from scattered, non-line-of-sight photons analyzed in a multimode and imaging interferometer for time-bins, combined with photon detection based on a 8 × 8 single-photon-detector-array. The observed time-bin visibility for scattered photons remained at a high 95% over a wide scattering angle range of −450 to +450, while the individual pixels in the detector array resolve or track an image in its field of view of ca. 0.5°. Using our method, we demonstrate the viability of two novel applications. Firstly, using scattered photons as an indirect channel for quantum communication thereby enabling non-line-of-sight quantum communication with background suppression, and secondly, using the combined arrival time and quantum coherence to enhance the contrast of low-light imaging and laser ranging under high background light. We believe our method will instigate new lines for research and development on applying photon coherence from scattered signals to quantum sensing, imaging, and communication in free-space environments.

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Section: Results Experimentsmentioning

confidence: 85%

Observing quantum coherence from photons scattered in free-space

Sajeed

Jennewein

2021

Light Sci Appl

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“…It generates optical perturbation in the air density, resulting in fluctuations in the refractive index in the atmosphere and instabilities in the optical transverse modulation [ 25 , 26 ]. Some studies were devoted to the influence of turbulent air on the filament distance [ 30 , 31 ], optical pulse broadening [ 32 ] and transverse filament wandering [ 33 , 34 ], etc. Due to the existence of turbulence, the vortex beam will suffer from serious beam expansion, drift and distortion.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Air Turbulence on Vortex Beams in Nonlinear Propagation

Zhu

Sun

et al. 2023

Sensors

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Vortex beams with orthogonality can be widely used in atmospheric applications. We numerically analyzed the statistical regularities of vortex beams propagating through a lens or an axicon with different series of turbulent air phase screens. The simulative results revealed that the distortion of the transverse intensity was sensitive to the location and the structure constant of the turbulence screen. In addition, the axicon can be regarded as a very useful optical device, since it can not only suppress the turbulence but also maintain a stable beam pattern. We further confirmed that a vortex beam with a large topological charge can suppress the influence of air turbulence. Our outcomes are valuable for many applications in the atmospheric air, especially for optical communication and remote sensing.

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“…Wave-front distortions are also expected to perturb the dynamic balance between Kerr self-focusing and plasma defocusing in the filaments. Experimental and theoretical studies were devoted to the influence of air turbulence on filament distance [12,13], filament survival rate [14,15], transverse filament wandering [16,17], filament spectral characteristics [18], optical pulse broadening [19], the enhancement of multifilament generation and filament-induced fluorescence [20,21], triggering filamentation using turbulence [22], and beam shaping that suppresses turbulence [23]. Trivial changes in filamentation have a great impact on sensitivity during remote sensing.…”

Section: Introductionmentioning

confidence: 99%

Beam Wander Restrained by Nonlinearity of Femtosecond Laser Filament in Air

Guo

Sun

Liu

et al. 2022

Sensors

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The filamentation process under atmospheric turbulence is critical to its remote-sensing application. The effects of turbulence intensity and location on the spatial distribution of femtosecond laser filaments in the air were studied. The experimental results show that the nonlinear effect of the filament can restrain the beam wander. When the turbulence intensity was 3.31×10−13 cm−2/3, the mean deviation of the wander of the filament center was only 27% of that of the linear transmitted beam. The change in turbulence location would lead to a change in the standard deviation of the beam centroid drift. Results also show that the filament length would be shortened, and that the filament would end up earlier in a turbulent environment. Since the filamentation-based LIDAR has been highly expected as an evolution multitrace pollutant remote-sensing technique, the study promotes our understanding of how turbulence influences filamentation and advances atmospheric remote sensing by applying a filament.

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Enhanced optical pulse broadening in free-space optical links due to the radiative effects of atmospheric aerosols

Cited by 10 publications

References 27 publications

Observing quantum coherence from photons scattered in free-space

Observing quantum coherence from photons scattered in free-space

The Effect of Air Turbulence on Vortex Beams in Nonlinear Propagation

Beam Wander Restrained by Nonlinearity of Femtosecond Laser Filament in Air

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