Real-Time Phase Conjugation of Vector Vortex Beams

Oliveira, André Gonçalves de; Arruda, M. F. Z.; Soares, W. C.; Walborn, S. P.; Gomes, Rafael M.; Araújo, R. Medeiros de; Ribeiro, P. H. Souto

doi:10.1021/acsphotonics.9b01524

“…Significantly less work has gone into similar techniques and tools for vector beams. Recent studies have looked into the correction of polarisation errors in vector modes but the application to atmospheric turbulence compensation is still in its infancy [180][181][182][183][184][185][186].…”

Section: Correction Schemesmentioning

confidence: 99%

Structured Light in Turbulence

Cox

¹

,

Mphuthi

²

,

Nape

³

et al. 2021

IEEE J. Select. Topics Quantum Electron.

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Optical communication is an integral part of the modern economy, having all but replaced electronic communication systems. Future growth in bandwidth appears to be on the horizon using structured light, encoding information into the spatial modes of light, and transmitting them down fibre and free-space, the latter crucial for addressing last mile and digitally disconnected communities. Unfortunately, patterns of light are easily distorted, and in the case of free-space optical communication, turbulence is a significant barrier. Here we review recent progress in structured light in turbulence, first with a tutorial style summary of the core concepts, before highlighting the present state-of-the-art in the field. We support our review with new experimental studies that reveal which types of structured light are best in turbulence, the behaviour of vector versus scalar light in turbulence, the trade-off of diversity and multiplexing, and how turbulence models can be exploited for enhanced optical signal processing protocols. This comprehensive treatise will be invaluable to the large communities interested in free-space optical communication with spatial modes of light.

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“…Significantly less work has gone into similar techniques and tools for vector beams. Recent studies have looked into the correction of polarisation errors in vector modes but the application to atmospheric turbulence compensation is still in its infancy [160][161][162][163][164][165][166].…”

Section: Correction Schemesmentioning

confidence: 99%

Structured Light in Turbulence

Cox,

Mphuthi,

Nape

et al. 2020

Preprint

View full text Add to dashboard Cite

Optical communication is an integral part of the modern economy, having all but replaced electronic communication systems. Future growth in bandwidth appears to be on the horizon using structured light, encoding information into the spatial modes of light, and transmitting them down fibre and free-space, the latter crucial for addressing last mile and digitally disconnected communities. Unfortunately, patterns of light are easily distorted, and in the case of free-space optical communication, turbulence is a significant barrier. Here we review recent progress in structured light in turbulence, first with a tutorial style summary of the core concepts, before highlighting the present state-of-the-art in the field. We support our review with new experimental studies that reveal which types of structured light are best in turbulence, the behaviour of vector versus scalar light in turbulence, the trade-off of diversity and multiplexing, and how turbulence models can be exploited for enhanced optical signal processing protocols. This comprehensive treatise will be invaluable to the large communities interested in free-space optical communication with spatial modes of light.

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“…Very recently, however, a meta-surface (J plate) using intracavity in a compact laser has led to direct control of the angular momentum of visible light with OAM quantum numbers l >100 as well as non-symmetric vector vortex beams lasing simultaneously on independent OAM states with Δ l = 90 apart [ 11 ]. This remarkable development is set to continue [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

Laser–Material Interactions of High-Quality Ultrashort Pulsed Vector Vortex Beams

Yu

¹

,

Perrie

²

,

Sierra

³

et al. 2021

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Diffractive multi-beams based on 1 × 5 and 2 × 2 binary Dammann gratings applied to a spatial light modulator (SLM) combined with a nanostructured S-wave plate have been used to generate uniform multiple cylindrical vector beams with radial and azimuthal polarizations. The vector quality factor (concurrence) of the single vector vortex beam was found to be C = 0.95 ± 0.02, hence showing a high degree of vector purity. The multi-beams have been used to ablate polished metal samples (Ti-6Al-4V) with laser-induced periodic surface structures (LIPSS), which confirm the polarization states unambiguously. The measured ablation thresholds of the ring mode radial and azimuthal polarizations are close to those of a Gaussian mode when allowance is made for the expected absolute intensity distribution of a ring beam generated from a Gaussian. In addition, ring mode vortex beams with varying orbital angular momentum (OAM) exhibit the same ablation threshold on titanium alloy. Beam scanning with ring modes for surface LIPSS formation can increase micro-structuring throughput by optimizing fluence over a larger effective beam diameter. The comparison of each machined spot was analysed with a machine learning method—cosine similarity—which confirmed the degree of spatial uniformity achieved, reaching cosθ > 0.96 and 0.92 for the 1 × 5 and 2 × 2 arrays, respectively. Scanning electron microscopy (SEM), optical microscopy and white light surface profiling were used to characterize and quantify the effects of surface modification.

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Real-Time Phase Conjugation of Vector Vortex Beams

Cited by 20 publications

References 45 publications

Structured Light in Turbulence

Structured Light in Turbulence

Structured Light in Turbulence

Laser–Material Interactions of High-Quality Ultrashort Pulsed Vector Vortex Beams

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