Optical storage of circular airy beam in atomic vapor

The realization of quantum storage of spatial light field is of great significance to the construction of high-dimensional quantum repeater.In this paper,we experimentally realize the storage and retrieval of circular Airy beams(CABs)by using theΛ-type three-level energy system based on the electromagnetically induced transparency in a hot rubidium atomic vapor cell.The weak probe beam field is modulated with phase distribution of CABs by a spatial light modulator.We store the probe circular Airy beam(CAB)into the rubidium atomic vapor cell and retrieve it after the demanded delay.We quantitatively analyze the storage results and give corresponding theoretical explanations.Moreover,we investigate the autofocusing and self-healing effect of the retrieved CAB,which indicates that the properties and beam shape of CAB maintain well after storage.Our work will have potential applications in the storage of high-dimensional quantum information,and is also useful for improving the channel capacities of quantum internet.

Atomic optical spatial mode extractor for vector beams based on polarization-dependent absorption

Vector beams with spiral phase and spatially varying polarization profiles have many applications from optical micromanipulation to materials processing. Here, we propose and demonstrate an atomic spatial mode extracting scheme for the vector beam based on polarization-dependent absorption in the atom vapor. By employing the linear polarization pump beam which induces polarization sensitive absorption in the atomic ensemble, a counter-propagated weak probe vector beam is extracted by spatial absorption, and extracted part still maintains the original polarization and the vortex phase.The topological charges of the extracted mode are verified by interfering with the Gaussian beam, and it can be found that the orbital angular momentum is conserved in the extracting process. Our work will have potential applications in non-destructive spatial mode identification, and is also useful for studying higher-dimensional quantum information based on atomic ensembles.

Microstructural heterogeneity and bonding strength of planar interface formed in additive manufacturing of Al-Mg-Si alloy based on friction and extrusion

Single-pass deposits of 6061 aluminum alloy with a single-layer thickness of 4 mm were fabricated by force-controlled friction-and extrusion-based additive manufacturing.The formation characteristics of the interface,which were achieved by using a featureless shoulder,were investigated and elucidated.The microstructure and bonding strength of the final build both with and without heat treatment were explored.A pronounced microstructural heterogeneity was observed throughout the thickness of the final build.Grains at the interface with Cu,{213}<111>,and Goss orientations prevailed,which were refined to approximately 4.0μm.Nearly all of the hardening precipitates were dissolved,resulting in the bonding interface displaying the lowest hardness.The fresh layer,subjected to thermal processes and plastic deformation only once,was dominated by a strong recrystallization texture with a Cube orientation.The previous layer,subjected twice to thermal processes and plastic deformation,was governed by P-and Goss-related components.The ultimate tensile strength along the build direction in asdeposited and heat-treated states could reach 57.0%and 82.9%of the extruded 6061-T651 aluminum alloy.