Tailoring arbitrary hybrid Poincaré beams through a single hologram

Author(s):

Shiyao Fu and Yanwang Zhai and Tonglu Wang and Ci Yin and Chunqing Gao

Abstract:

“Hybrid Poincaré beams (HPBs) are a kind of structure field with anisotropic polarizations. Here, we demonstrate an approach to tailor HPBs with arbitrary states, through encoding a single hologram on a liquid-crystal display device along with a stable optical system. The state of the obtained HPB is determined only by the encoded holograms with special design, which means it is not necessary to adjust any optical elements or hardware when generating various HPB states. Moreover, perfect HPBs can also be generated through the proposed scheme. In the experiment, the obtained HPBs are analyzed through a polarizer and a special parameter S3/S0, showing good agreement with prediction. This work opens an insight in encoding single holograms for tailoring arbitrary HPBs and inspires various applications.”

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Publication: Applied Physics Letters

Issue/Year/DOI: Applied Physics Letters Volume 111, Issue 21
DOI: 10.1063/1.5008954

Non-diffractive Bessel-Gauss beams for the detection of rotating object free of obstructions

Author(s):

Shiyao Fu and Tonglu Wang and Zheyuan Zhang and Yanwang Zhai and Chunqing Gao

Abstract:

“Bessel-Gauss beams carrying orbital angular momentum are widely known for their non-diffractive or self-reconstructing performance, and have been applied in lots of domains. Here we demonstrate that, by illuminating a rotating object with high-order Bessel-Gauss beams, a frequency shift proportional to the rotating speed and the topological charge is observed. Moreover, the frequency shift is still present once an obstacle exists in the path, in spite of the decreasing of received signals. Our work indicates the feasibility of detecting rotating objects free of obstructions, and has potential as obstruction-immune rotation sensors in engine monitoring, aerological sounding, and so on.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express , Vol. 25, Issue 17, pp. 20098- 20108 (2018)
DOI: 10.1364/OE.25.020098

Free-space optical communication link using perfect vortex beams carrying orbital angular momentum ({OAM})

Author(s):

Fuquan Zhu and Sujuan Huang and Wei Shao and Jie Zhang and Musheng Chen and Weibing Zhang and Junzhang Zeng

Abstract:

“We experimentally demonstrate a free-space optical communication link using perfect vortex beams. Perfect vortex beams with different topological charges are generated using a phase-modulation-type spatial light modulator (SLM) loaded with novel phase holograms based on the Bessel function. With the help of a
microscope objective and simple lens, perfect vortex beams are transmitted effectively for a certain distance. After completing the demodulation of perfect vortex beams carrying OFDM 16-QAM signals and a series of offline processing on the Gaussian bright spot demodulated from the perfect vortex beams, we also achieve a communication link. The constellations and mean bit error rates (BER) of subcarriers are shown.”

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Publication: Optics Communications

Issue/Year/DOI: Optics Communications Volume 396, Pages 50-57
DOI: 10.1016/j.optcom.2017.03.023

Robust laser beam engineering using polarization and angular momentum diversity

Author(s):

Priyanka Lochab and P. Senthilkumaran and Kedar Khare

Abstract:

“We describe a laser beam engineered to carry l = 0 and l = 1 orbital angular momentum (OAM) states in orthogonal polarizations. It is observed that on collinear transmission through a random phase screen, the far field diffraction intensity patterns for the individual polarization states are complementary with significant negative correlation. As a result the combined intensity profile for the beam remains robust against time varying phase fluctuations. In our simulation and experiment the SNR for the central lobe of the combined far-field diffraction pattern defined as mean divided by the standard deviation of intensity values shows significant improvement over that for individual polarizations. The concept of polarization and OAM diversity as demonstrated here can be considered valuable for robust laser beam engineering without the requirement of any active real-time correction methods.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express, Vol. 25 , Issue 15 , pp. 17524-17524 (2018)
DOI: 10.1364/OE.25.017524

Selective acquisition of multiple states on hybrid Poincare sphere

Author(s):

Shiyao Fu and Tonglu Wang and Zheyuan Zhang and Yanwang Zhai and Chunqing Gao

Abstract:

“We experimentally demonstrate an approach to acquire multiple beams on a hybrid Poincare
sphere, where different states are present at various diffraction orders. Moreover, the state in each
diffraction order is controllable. Our scheme is accomplished by employing liquid crystal spatial
light modulators, which act as anisotropic polarization diffraction gratings. The multiple states
generated in the experiment, with various polarization distributions, are verified by a polarizer and
a tilted lens, showing good agreement with the prediction. Such a proposed scheme has potential
applications in the domains as laser machining, nanoparticle manipulations, and so on.”

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Publication: Applied Physics Letters
Issue/Year/DOI: Applied Physics Letters Volume 110, Issue 19
DOI: 10.1063/1.4983284

Dimensional properties of Laguerre–Gaussian vortex beams

Author(s):

Jie Zhang, Su-Juan Huang, Fu-Quan Zhu, Wei Shao, and Mu-Sheng Chen

Abstract:

“We derive and analyze the dimensional properties of Laguerre–Gaussian vortex beams theoretically and numerically. The analytical expressions of inner and outer radii are given out and proved to be proportional to the transverse beam size, when the topological charge remains. The ratio of the outer and inner radius only depends on the topological charge, having nothing to do with the waist radius and the propagation distance, and the ratio decreases as the topological charge increases. Using a spatial light modulator loaded with computer-generated holograms, we generate vortex beams. The experimental results are in good agreement with our numerical simulations. This research may provide useful insights into the study of the optical vortex beam and its further applications.”

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Publication: Applied Optics

Issue/Year/DOI: Applied Optics Volume 56, Issue 12 pp. 3556-3561 (2017)
DOI: 10.1364/AO.56.003556

Bessel beams with spatial oscillating polarization

Author(s):

Fu, Shiyao and Zhang, Shikun and Gao, Chunqing

Abstract:

“Bessel beams are widely used in optical metrology mainly because of their large Rayleigh range (focal length). Radial/azimuthal polarization of such beams is of interest in the fields of material processing, plasma absorption or communication. In this paper an experimental set-up is presented, which generates a Bessel-type vector beam with a spatial polarization, oscillating along the optical axis, when propagating in free space. A first holographic axicon (HA) HA1 produces a normal, linearly polarized Bessel beam, which by a second HA2 is converted into the spatial oscillating polarized beam. The theory is briefly discussed, the set-up and the experimental results are presented in detail.”

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Publication: Scientific Reports

Issue/Year/DOI:  Scientific Reports volume 6, Article number: 30765 (2016)
DOI: 10.1038/srep30765

Detection of Bessel beams with digital axicons

Author(s):

Abderrahmen Trichili and Thandeka Mhlanga and Yaseera Ismail and Filippus S. Roux and Melanie McLaren and Mourad Zghal and Andrew Forbes

Abstract:

“We propose a simple method for the detection of Bessel beams with arbitrary radial and azimuthal indices, and then demonstrate it in an all-digital setup with a spatial light modulator. We confirm that the fidelity of the detection method is very high, with modal cross-talk below 5%, even for high orbital angular momentum carrying fields with long propagation ranges. To illustrate the versatility of the approach we use it to observe the modal spectrum changes during the self-reconstruction process of Bessel beams after encountering an obstruction, as well as to characterize modal distortions of Bessel beams propagating through atmospheric turbulence.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express, Vol. 22 , Issue 14, pp. 17553- 17560 (2014)
DOI: 10.1364/OE.22.017553

Optical eigenmodes; exploiting the quadratic nature of the energy flux and of scattering interactions

Author(s):

Mazilu, Michael and Baumgartl, J and Kosmeier, S and Dholakia, K

Abstract:

“Abstract: We report a mathematically rigorous technique which facilitates the optimization of various optical properties of electromagnetic fields in free space and including scattering interactions. The technique exploits the linearity of electromagnetic fields along with the quadratic nature of the intensity to define specific Optical Eigenmodes (OEi) that are pertinent to the interaction considered. Key applications include the optimization of the size of a focused spot, the transmission through sub-wavelength apertures, and of the optical force acting on microparticles. We verify experimentally the OEi approach by minimising the size of a focused optical field using a superposition of Bessel beams.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Volume 19, Issue 2 pp.933-945 (2011)
DOI: 10.1364/OE.19.000933