Spin-orbit interaction of light induced by transverse spin angular momentum engineering

Author(s):

Zengkai Shao and Jiangbo Zhu and Yujie Chen and Yanfeng Zhang and Siyuan Yu

Abstract:

“The investigations on optical angular momenta and their interactions have broadened our knowledge of light’s behavior at sub-wavelength scales. Recent studies further unveil the extraordinary characteristics of transverse spin angular momentum in confined light fields and orbital angular momentum in optical vortices. Here we demonstrate a direct interaction between these two intrinsic quantities of light. By engineering the transverse spin in the evanescent wave of a whispering-gallery-mode-based optical vortex emitter, a spin-orbit interaction is observed in generated vortex beams. Inversely, this unconventional spin-orbit interplay further gives rise to an enhanced spin-direction locking effect in which waveguide modes are unidirectionally excited, with the directionality jointly controlled by the spin and orbital angular momenta states of light. The identification of this previously unknown pathway between the polarization and spatial degrees of freedom of light enriches the spin-orbit interaction phenomena, and can enable various functionalities in applications such as communications and quantum information processing.”

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Publication: Nature Communications

Issue/Year/DOI: Nature Communicationsvolume 9, Article number: 926 (2018)
DOI: 10.1038/s41467-018-03237-5

Synthesis of light needles with tunable length and nearly constant irradiance.

Author(s):

Martínez-Herrero, Rosario and Maluenda, David and Juvells, Ignasi and Carnicer, Artur

Abstract:

“We introduce a new method for producing optical needles with tunable length and almost constant irradiance based on the evaluation of the on-axis power content of the light distribution at the focal area. According to theoretical considerations, we propose an adaptive modulating continuous function that presents a large derivative and a zero value jump at the entrance pupil of the focusing system. This distribution is displayed on liquid crystal devices using holographic techniques. In this way, a polarized input beam is shaped and subsequently focused using a high numerical aperture (NA) objective lens. As a result, needles with variable length and nearly constant irradiance are produced using conventional optics components. This procedure is experimentally demonstrated obtaining a 53λ-long and 0.8λ-wide needle.”

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Publication: Scientific Reports

Issue/Year/DOI: Scientific Reportsvolume 8, Article number: 2657 (2018)
DOI: 10.1038/s41598-018-21007-7

Investigation of albumin-derived perfluorocarbon-based capsules by holographic optical trapping

Author(s):

Jannis Köhler and Jegor Ruschke and Katja Bettina Ferenz and Cemal Esen and Michael Kirsch and Andreas Ostendorf

Abstract:

“Albumin-derived perfluorocarbon-based capsules are promising as artificial oxygen carriers with high solubility. However, these capsules have to be studied further to allow initial human clinical tests. The aim of this paper is to provide and characterize a holographic optical tweezer to enable contactless trapping and moving of individual capsules in an environment that mimics physiological (in vivo) conditions most effectively in order to learn more about the artificial oxygen carrier behavior in blood plasma without recourse to animal experiments. Therefore, the motion behavior of capsules in a ring shaped or vortex beam is analyzed and optimized on account of determination of the optical forces in radial and axial direction. In addition, due to the customization and generation of dynamic phase holograms, the optical tweezer is used for first investigations on the aggregation behavior of the capsules and a statistical evaluation of the bonding in dependency of different capsule sizes is performed. The results show that the optical tweezer is sufficient for studying individual perfluorocarbon-based capsules and provide information about the interaction of these capsules for future use as artificial oxygen carriers.”

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Publication: Biomed. Opt. Express

Issue/Year/DOI: Biomedical Optics Express Vol. 9,Issue 2, pp. 743-754(2018)

DOI: 10.1364/BOE.9.000743

 

Interactive Holographic Display Based on Finger Gestures.

Author(s):

Yamada, Shota and Kakue, Takashi and Shimobaba, Tomoyoshi and Ito, Tomoyoshi

Abstract:

“In this paper, we demonstrate an interactive, finger-sensitive system which enables an observer to intuitively handle electro-holographic images in real time. In this system, a motion sensor detects finger gestures (swiping and pinching) and translates them into the rotation and enlargement/reduction of the holographic image, respectively. By parallelising the hologram calculation using a graphics processing unit, we realised the interactive handling of the holographic image in real time. In a demonstration of the system, we used a Leap Motion sensor and a phase modulation-type spatial light modulator with 1,920 × 1,080 pixels and a pixel pitch of 8.0 µm × 8.0 µm. The constructed interactive finger-sensitive system was able to rotate a holographic image composed of 4,096 point light sources using a swiping gesture and enlarge or reduce it using a pinching gesture in real time. The average calculation speed was 27.6 ms per hologram. Finally, we extended the constructed system to a full-colour reconstruction system that generates a more realistic three-dimensional image. The extended system successfully allowed the handling of a full-colour holographic image composed of 1,709 point light sources with a calculation speed of 22.6 ms per hologram.”

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Publication: Scientific Reports

Issue/Year/DOI: Scientific Reportsvolume 8, Article number: 2010 (2018)
DOI: 10.1038/s41598-018-20454-6

Real-time colour hologram generation based on ray-sampling plane with multi-GPU acceleration.

Author(s):

Sato, Hirochika and Kakue, Takashi and Ichihashi, Yasuyuki and Endo, Yutaka and Wakunami, Koki and Oi, Ryutaro and Yamamoto, Kenji and Nakayama, Hirotaka and Shimobaba, Tomoyoshi and Ito, Tomoyoshi

Abstract:

“Although electro-holography can reconstruct three-dimensional (3D) motion pictures, its computational cost is too heavy to allow for real-time reconstruction of 3D motion pictures. This study explores accelerating colour hologram generation using light-ray information on a ray-sampling (RS) plane with a graphics processing unit (GPU) to realise a real-time holographic display system. We refer to an image corresponding to light-ray information as an RS image. Colour holograms were generated from three RS images with resolutions of 2,048 × 2,048; 3,072 × 3,072 and 4,096 × 4,096 pixels. The computational results indicate that the generation of the colour holograms using multiple GPUs (NVIDIA Geforce GTX 1080) was approximately 300-500 times faster than those generated using a central processing unit. In addition, the results demonstrate that 3D motion pictures were successfully reconstructed from RS images of 3,072 × 3,072 pixels at approximately 15 frames per second using an electro-holographic reconstruction system in which colour holograms were generated from RS images in real time.”

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Publication: Scientific Reports

Issue/Year/DOI:  Scientific Reports Volume 8, Article number: 1500 (2018)
DOI: 10.1038/s41598-018-19361-7

Controllable mode transformation in perfect optical vortices

Author(s):

Xinzhong Li and Haixiang Ma and Chuanlei Yin and Jie Tang and Hehe Li and Miaomiao Tang and Jingge Wang and Yuping Tai and Xiufang Li and Yishan Wang

Abstract:

“We report a novel method to freely transform the modes of a perfect optical vortex (POV). By adjusting the scaling factor of the Bessel–Gauss beam at the object plane, the POV mode transformation can be easily controlled from circle to ellipse with a high mode purity. Combined with the modulation of the cone angle of an axicon, the ellipse mode can be freely adjusted along the two orthogonal directions. The properties of the “perfect vortex” are experimentally verified. Moreover, fractional elliptic POVs with versatile modes are presented, where the number and position of the gaps are controllable. These findings are significant for applications that require the complex structured optical field of the POV.”

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Publication: Opt. Express

Issue/Year/DOI: Opt. Express, Vol. 26, Issue 2, pp. 651-662 (2018)
DOI: 10.1364/OE.26.000651

Time multiplexing technique of holographic view and Maxwellian view using a liquid lens in the optical see-through head mounted display

Author(s):

Jin Su Lee and Yoo Kwang Kim and Yong Hyub Won

Abstract:

“We report a liquid lens based optical see-through head mounted display that can simultaneously display both a maxwellian view and a hologram. Holograms are reconstructed by an angular spectrum layer based synthesis method. A hologram and Maxwellian view are simultaneously displayed by focusing the liquid lens from 0 D to 20 D with 60 Hz. The hologram is reconstructed at a position 1.5 m from the eye, and it is confirmed that the Maxwellian view is clear, even if the focus of the eye changes from 50 cm to 1.7 m. In the proposed system, the liquid lens acts as a low-pass filter. Since the PSNR is about 23 dB in the currently used 10 mm diameter liquid lens, the image quality is not adequate. However, we successfully verify the feasibility of our proposed system. In addition, if a large diameter liquid lens of 30 mm or more is applied, excellent image quality of 30 dB or more can be realized.”

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Publication: Opt. Express

Issue/Year/DOI: Opt. Express, Vol. 26, Issue 2, pp. 2149-2159 (2018)
DOI: 10.1364/OE.26.002149

Focusing behavior of the fractal vector optical fields designed by fractal lattice growth model

Author(s):

Xu-Zhen Gao and Yue Pan and Meng-Dan Zhao and Guan-Lin Zhang and Yu Zhang and Chenghou Tu and Yongnan Li and Hui-Tian Wang

Abstract:

“We introduce a general fractal lattice growth model, significantly expanding the application scope of the fractal in the realm of optics. This model can be applied to construct various kinds of fractal “lattices” and then to achieve the design of a great diversity of fractal vector optical fields (F-VOFs) combinating with various “bases”. We also experimentally generate the F-VOFs and explore their universal focusing behaviors. Multiple focal spots can be flexibly enginnered, and the optical tweezers experiment validates the simulated tight focusing fields, which means that this model allows the diversity of the focal patterns to flexibly trap and manipulate micrometer-sized particles. Furthermore, the recovery performance of the F-VOFs is also studied when the input fields and spatial frequency spectrum are obstructed, and the results confirm the robustness of the F-VOFs in both focusing and imaging processes, which is very useful in information transmission.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express, Vol. 26, Issue 2, pp. 1597-1614(2018)
DOI: 10.1364/OE.26.001597

Rotating of low-refractive-index microparticles with a quasi-perfect optical vortex

Author(s):

Yansheng Liang and Ming Lei and Shaohui Yan and Manman Li and Yanan Cai and Zhaojun Wang and Xianghua Yu and Baoli Yao

Abstract:

“Low-refractive-index microparticles, such as hollow microspheres, have shown great significance in some applications, such as biomedical sensing and targeted drug delivery. However, optical trapping and manipulation of low-refractive-index microparticles are challenging, owing to the repelling force exerted by typical optical traps. In this paper, we demonstrated optical trapping and rotating of large-sized low-refractive-index microparticles by using quasi-perfect optical vortex (quasi-POV) beams, which were generated by Fourier transform of high-order quasi-Bessel beams. Numerical simulation was carried out to characterize the focusing property of the quasi-POV beams. The dynamics of low-refractive-index microparticles in the quasi-POV with various topological charges was investigated in detail. To improve the trapping and rotating performances of the vortex, a point trap was introduced at the center of the ring. Experimental results showed that the quasi-POV was preferable for manipulation of large-sized low-refractive-index microparticles, with its control of the particles’ rotating velocity dependent only on the topological charge due to the unchanged orbital radius.”

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Publication: Applied Optics
Issue/Year/DOI: Applied Optics Volume 57, Issue 1 pp. 79-84
DOI: 10.1364/ao.57.000079

Demonstration of a vectorial optical field generator with adaptive close loop control

Author(s):

Jian Chen and Lingjiang Kong and Qiwen Zhan

Abstract:

“We experimentally demonstrate a vectorial optical field generator (VOF-Gen) with an adaptive close loop control. The close loop control capability is illustrated with the calibration of polarization modulation of the system. To calibrate the polarization ratio modulation, we generate 45° linearly polarized beam and make it propagate through a linear analyzer whose transmission axis is orthogonal to the incident beam. For the retardation calibration, circularly polarized beam is employed and a circular polarization analyzer with the opposite chirality is placed in front of the CCD as the detector. In both cases, the close loop control automatically changes the value of the corresponding calibration parameters in the pre-set ranges to generate the phase patterns applied to the spatial light modulators and records the intensity distribution of the output beam by the CCD camera. The optimized calibration parameters are determined corresponding to the minimum total intensity in each case. Several typical kinds of vectorial optical beams are created with and without the obtained calibration parameters, and the full Stokes parameter measurements are carried out to quantitatively analyze the polarization distribution of the generated beams. The comparisons among these results clearly show that the obtained calibration parameters could remarkably improve the accuracy of the polarization modulation of the VOF-Gen, especially for generating elliptically polarized beam with large ellipticity, indicating the significance of the presented close loop in enhancing the performance of the VOF-Gen.”

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Publication: Review of Scientific Instruments

Issue/Year/DOI: Review of SCientific Instruments 88, 125111 (2017)
DOI: 10.1063/1.4999656