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.”

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

Laser surface structuring of diamond with ultrashort Bessel beams

Author(s):

Sanjeev Kumar, Shane M. Eaton, Monica Bollani, Belén Sotillo, Andrea Chiappini, Maurizio Ferrari, Roberta Ramponi, Paolo Di Trapani, Ottavia Jedrkiewicz

Abstract:

“We investigate the effect of ultrafast laser surface machining on a monocrystalline synthetic diamond sample by means of pulsed Bessel beams. We discuss the differences of the trench-like microstructures generated in various experimental conditions, by varying the beam cone angle, the energy and pulse duration, and we present a brief comparison of the results with those obtained with the same technique on a sapphire sample. In diamond, we obtain V-shaped trenches whose surface width varies with the cone angle, and which are featured by micrometer sized channels having depths in the range of 10–20 μm. By laser writing crossed trenches we are also able to create and tailor on the diamond surface pillar-like or tip-like microstructures potentially interesting for large surface functionalization, cells capturing and biosensing.”

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Publication: Scientific Reports

Issue/Year/DOI: Scientific Reports 8, Article number: 14021 (2018)

DOI: 10.1038/s41598-018-32415-0

Generation of elliptic perfect optical vortex and elliptic perfect vector beam by modulating the dynamic and geometric phase

Author(s):

Delin Li and Chenliang Chang and Shouping Nie and Shaotong Feng and Jun Ma and Caojin Yuan

Abstract:

“We propose a method for generating an elliptic perfect vector beam (EPVB) by modulating the dynamic and geometric phases. It is theoretically demonstrated that the shape of the beam can be changed from circle to ellipse by setting the scale factor m of the dynamic phase, but the diameter of it is independent on the topological charge and the polarization order. Since the geometric phases provided by the dialectic Q-plate vary with the polarization state of the illumination beam, EPVB can be converted to the elliptic perfect optical vortex (EPOV) beam by changing the polarization state of the illuminating beam. Therefore, we also provide an alternative method to generate the EPOV beam. The experimental results agree well with the theoretical expectations.”

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Publication: Applied Physics Letters
Issue/Year/DOI: Applied Physics Letters Volume 113, Issue 12

DOI: 10.1063/1.5048327

Nonlinear generation of Airy vortex beam

Author(s):
Hui Li and Haigang Liu and Xianfeng Chen

Abstract:

“Recently, hybrid beams have sparked considerable interest because of their properties coming from different kinds of beams at the same time. Here, we experimentally demonstrate Airy vortex beam generation in the nonlinear frequency conversion process when the fundamental wave with its phase modulated by a spatial light modulator is incident into a homogeneous nonlinear medium. In our experiments, second harmonic Airy circle vortex beams and Airy ellipse vortex beams were generated and the topological charge was also measured. The parabolic trajectory of those Airy vortex beams can be easily adjusted by altering the fundamental wave phase. This study provides a simple way to generate second harmonic Airy vortex beams, which may broaden its future use in optical manipulation and light-sheet microscopy.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Volume 26, Issue 16
DOI: 10.1364/oe.26.021204

Multiple-plane image formation by Walsh zone plates

Author(s):

Federico Machado, Vicente Ferrando, Fernando Giménez, Walter D. Furlan, and Juan A. Monsoriu

Abstract:

“A radial Walsh filter is a phase binary diffractive optical element characterized by a set of concentric rings that take the phase values 0 or π, corresponding to the values + 1 or −1 of a given radial Walsh function. Therefore, a Walsh filter can be re-interpreted as an aperiodic multifocal zone plate, capable to produce images of multiple planes simultaneously in a single output plane of an image forming system. In this paper, we experimentally demonstrate for the first time the focusing capabilities of these structures. Additionally, we report the first achievement of images of multiple-plane objects in a single image plane with these aperiodic diffractive lenses.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Volume 26, Issue 16
DOI: 10.1364/OE.26.021210

Shaping the on-axis intensity profile of generalized Bessel beams by iterative optimization methods

Author(s):

Runze Li and Xianghua Yu and Tong Peng and Yanlong Yang and Baoli Yao and Chunmin Zhang and Tong Ye
Abstract:

“The Bessel beam belongs to a typical class of non-diffractive optical fields that are characterized
by their invariant transverse profiles with the beam propagation. The extended and uniformed
intensity profile in the axial direction is of great interest in many applications. However, ideal
Bessel beams only rigorously exist in theory; the Bessel beams generated in the experiment are
always quasi-Bessel beams with finite focal extensions and varying intensity profiles along the
propagation axis. The ability to shape the on-axis intensity profile to meet specific needs is
essential for many applications. Here, we demonstrate an iterative optimization based approach
to engineer the on-axis intensity of Bessel beams through design and fine-tune processes.
Starting with a standard axicon phase mask, the design process uses the computed on-axis beam
profile as a feedback in the iterative optimization process, which searches for the optimal radial
phase distribution that can generate a so-called generalized Bessel beam with the desired on-axis
intensity profile. The fine-tune process repeats the optimization processing by using the adjusted
target on-axis profile according to the measured one. Our proposed method has been
demonstrated in engineering several quasi-Bessel beams with customized on-axis profiles. The
high accuracy and high energy throughput merit its use in many applications. This method is also
suitable to engineer higher-order Bessel beams by adding appropriate vortex phases into the
designed phase mask.”

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Publication: Journal of Optics

Issue/Year/DOI: Journal of Optics, Volume 20, Number 8 (2018)

DOI: 10.1088/2040-8986/aace46

Three-dimensional vectorial multifocal arrays created by pseudo-period encoding

Author(s):

Tingting Zeng and Chenliang Chang and Zhaozhong Chen and Hui-Tian Wang and Jianping Ding

Abstract:

“Multifocal arrays have been attracting considerable attention recently owing to their potential
applications in parallel optical tweezers, parallel single-molecule orientation determination,
parallel recording and multifocal multiphoton microscopy. However, the generation of vectorial
multifocal arrays with a tailorable structure and polarization state remains a great challenge, and
reports on multifocal arrays have hitherto been restricted either to scalar focal spots without
polarization versatility or to regular arrays with fixed spacing. In this work, we propose a specific
pseudo-period encoding technique to create three-dimensional (3D) vectorial multifocal arrays
with the ability to manipulate the position, polarization state and intensity of each focal spot. We
experimentally validated the flexibility of our approach in the generation of 3D vectorial multiple
spots with polarization multiplicity and position tunability.”

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Publication: Journal of Optics

Issue/Year/DOI: Journal of Optics, Volume 20, Number 6
DOI: 10.1088/2040-8986/aac1de

Observing the cell in its native state: Imaging subcellular dynamics in multicellular organisms

Author(s):

Liu, Tsung-Li and Upadhyayula, Srigokul and Milkie, Daniel E. and Singh, Ved and Wang, Kai and Swinburne, Ian A. and Mosaliganti, Kishore R. and Collins, Zach M. and Hiscock, Tom W. and Shea, Jamien and Kohrman, Abraham Q. and Medwig, Taylor N. and Dambournet, Daphne and Forster, Ryan and Cunniff, Brian and Ruan, Yuan and Yashiro, Hanako and Scholpp, Steffen and Meyerowitz, Elliot M. and Hockemeyer, Dirk and Drubin, David G. and Martin, Benjamin L. and Matus, David Q. and Koyama, Minoru and Megason, Sean G. and Kirchhausen, Tom and Betzig, Eric

Abstract:

“True physiological imaging of subcellular dynamics requires studying cells within their parent organisms, where all the environmental cues that drive gene expression, and hence the phenotypes that we actually observe, are present. A complete understanding also requires volumetric imaging of the cell and its surroundings at high spatiotemporal resolution, without inducing undue stress on either. We combined lattice light-sheet microscopy with adaptive optics to achieve, across large multicellular volumes, noninvasive aberration-free imaging of subcellular processes, including endocytosis, organelle remodeling during mitosis, and the migration of axons, immune cells, and metastatic cancer cells in vivo. The technology reveals the phenotypic diversity within cells across different organisms and developmental stages and may offer insights into how cells harness their intrinsic variability to adapt to different physiological environments.”

 

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Publication: Science

Issue/Year/DOI: Science, Vol. 360, Issue 6386, (2018)
DOI: 10.1126/science.aaq1392

Generation of optical vortex array along arbitrary curvilinear arrangement

Author(s):

Lin Li and Chenliang Chang and Xiangzheng Yuan and Caojin Yuan and Shaotong Feng and Shouping Nie and Jianping Ding

Abstract:

“We propose an approach for creating optical vortex array (OVA) arranged along arbitrary curvilinear path, based on the coaxial interference of two width-controllable component curves calculated by modified holographic beam shaping technique. The two component curve beams have different radial dimensions as well as phase gradients along each beam such that the number of phase singularity in the curvilinear arranged optical vortex array (CA-OVA) is freely tunable on demand. Hybrid CA-OVA that comprises of multiple OVA structures along different respective curves is also discussed and demonstrated. Furthermore, we study the conversion of CA-OVA into vector mode that comprises of polarization vortex array with varied polarization state distribution. Both simulation and experimental results prove the performance of the proposed method of generating a complex structured vortex array, which is of significance for potential applications including multiple trapping of micro-sized particles.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express, Vol.26, Issue 8, pp. 9798- 9812 (2018)
DOI: 10.1364/OE.26.009798

Obstacle evasion in free-space optical communications utilizing Airy beams

Author(s):

Guoxuan Zhu and Yuanhui Wen and Xiong Wu and Yujie Chen and Jie Liu and Siyuan Yu
Abstract:

“A high speed free-space optical communication system capable of self-bending signal transmission around line-of-sight obstacles is proposed and demonstrated. Airy beams are generated and controlled to achieve different propagating trajectories, and the signal transmission characteristics of these beams around the obstacle are investigated. Our results confirm that, by optimizing their ballistic trajectories, Airy beams are able to bypass obstacles with more signal energy and thus improve the communication performance compared with normal Gaussian beams.”

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Publication: Optics Letters
Issue/Year/DOI: Optics Letters Volume 43, Issue 6, pp. 1203-1206 (2018)
DOI: 10.1364/OL.43.001203

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