Measuring orbital angular momentums of light based on petal interference patterns

Author(s):

Shengzhe Pan and Chunying Pei and Shuang Liu and Jin Wei and Di Wu and Zhanou Liu and Yaling Yin and Yong Xia and Jianping Yin

Abstract:

“We demonstrate an interferometric method to measure the topological charges of the vortex beams carrying orbital angular momentums (OAMs). The petal interference patterns are generated by combining modulated vortex beams and an unmodulated incident Gaussian beam reflected by a spatial light modulator. The number of petals is in agreement with the value of OAM that the modulated beam carries, by which we analyze the characteristic of interference patterns of integer OAM beams, including intensity profiles, phase profiles, and hologram structures. We also uncover the principle of how radial parameter l influences the hollow radius of OAM beams. Beams carrying non-integer orbital angular momentums are visualized with our method, from which we observe the evolution of a speckle generated by the decimal part of holograms. A kind of hologram is designed to prove that the petal near the singularity line is separated owing to the diffraction enhancement. All the experiment results agree well with the simulated results.”

Link to Publications Page

Publication: OSA Continuum
Issue/Year/DOI: OSA Continuum Volume 1, Issue 2 (2018)
DOI: 10.1364/OSAC.1.000451

Optical see-through holographic near-eye-display with eyebox steering and depth of field control

Author(s):
Jae-Hyeung Park and Seong-Bok Kim

Abstract:

“We propose an optical see-through holographic near-eye-display that can control the depth of field of individual virtual three-dimensional image and replicate the eyebox with dynamic steering. For optical see-through capability and eyebox duplication, a holographic optical element is used as an optical combiner where it functions as multiplexed tilted concave mirrors forming multiple copies of the eyebox. Fo1r depth of field control and eyebox steering, computer generated holograms of three-dimensional objects are synthesized with different ranges of angular spectrum. In optical experiment, it has been confirmed that the proposed system can present always-focused images with large depth of field and three-dimensional images at different distances with shallow depth of field at the same time without any time-multiplexing.”

Link to Publications Page

Publication: Optics Express

Issue/Year/DOI: Optics Express Volume 26, Issue 21
DOI: 10.1364/oe.26.027076

Self-healing high-dimensional quantum key distribution using hybrid spin-orbit Bessel states

Author(s):

Isaac Nape, Eileen Otte, Adam Vallés, Carmelo Rosales-Guzmán, Filippo Cardano, Cornelia Denz, and Andrew Forbes

Abstract:

“Using spatial modes for quantum key distribution (QKD) has become highly topical due to their infinite dimensionality, promising high information capacity per photon. However, spatial distortions reduce the feasible secret key rates and compromise the security of a quantum channel. In an extreme form such a distortion might be a physical obstacle, impeding line-of-sight for free-space channels. Here, by controlling the radial degree of freedom of a photon’s spatial mode, we are able to demonstrate hybrid high-dimensional QKD through obstacles with self-reconstructing single photons. We construct high-dimensional mutually unbiased bases using spin-orbit hybrid states that are radially modulated with a non-diffracting Bessel-Gaussian (BG) profile, and show secure transmission through partially obstructed quantum links. Using a prepare-measure protocol we report higher quantum state self-reconstruction and information retention for the non-diffracting BG modes as compared to Laguerre-Gaussian modes, obtaining a quantum bit error rate (QBER) that is up to 3× lower. This work highlights the importance of controlling the radial mode of single photons in quantum information processing and communication as well as the advantages of QKD with hybrid states.”

Link to Publications Page

Publication: Optics Express

Issue/Year/DOI: Optics Express Volume 26, Issue 21
DOI: 10.1364/OE.26.026946