scispace - formally typeset
Search or ask a question
Author

Yu Tokizane

Other affiliations: Hokkaido University
Bio: Yu Tokizane is an academic researcher from Chiba University. The author has contributed to research in topics: Optical vortex & Vortex. The author has an hindex of 7, co-authored 17 publications receiving 429 citations. Previous affiliations of Yu Tokizane include Hokkaido University.

Papers
More filters
Journal ArticleDOI
TL;DR: It is discovered that chiral nanoneedles fabricated by vortex laser ablation can be used to visualize the helicity of an optical vortex and it is found that optical vortices with the same total angular momentum are degenerate, and they generate nan oneedles with theSame chirality and spiral frequency.
Abstract: We discovered that chiral nanoneedles fabricated by vortex laser ablation can be used to visualize the helicity of an optical vortex. The orbital angular momentum of light determines the chirality of the nanoneedles, since it is transferred from the optical vortex to the metal. Only the spin angular momentum of the optical vortex can reinforce the helical structure of the created chiral nanoneedles. We also found that optical vortices with the same total angular momentum (defined as the sum of the orbital and spin angular momenta) are degenerate, and they generate nanoneedles with the same chirality and spiral frequency.

268 citations

Journal ArticleDOI
TL;DR: A new achromatic method to generate the optical vortex was proposed and supercontinuum optical vortex generation was experimentally demonstrated without spatial nor topological-charge dispersions.
Abstract: A new achromatic method to generate the optical vortex was proposed and supercontinuum optical vortex generation ranging approximately 500 to approximately 800 nm was experimentally demonstrated without spatial nor topological-charge dispersions. In addition, polarization evolution in our system using Jones vectors and matrices was discussed and the condition of the polarizer to transfer polarizations was elucidated. This method is useful for the application to time-resolved nonlinear spectroscopy utilizing ultrabroadband optical vortex pulses in topological materials such as ring-shaped crystals or annular materials.

77 citations

Journal ArticleDOI
TL;DR: The topological charges of the signal and idler output were investigated using a shearing interferometric technique employing a low-spatial-frequency transmission grating to generate tunable 2-μm optical vortex pulses with a topological charge of 1 or 2.
Abstract: We generated tunable 2-μm optical vortex pulses with a topological charge of 1 or 2 in the wavelength range 1.953–2.158 μm by realizing anisotropic transfer of the topological charge from the pump beam to the signal output in a vortex-pumped half-symmetric optical parametric oscillator. A maximum vortex output energy of 2.1 mJ was obtained at a pump energy of 22.8 mJ, which corresponds to a slope efficiency of 15%. The topological charges of the signal and idler output were investigated using a shearing interferometric technique employing a low-spatial-frequency transmission grating.

47 citations

Journal ArticleDOI
TL;DR: The current trends in stimulated Brillouin scattering and optical phase conjugation are overviewed in this paper, where the selected papers presented in the 2010 5th International Workshop on SBS and PHYP are summarized.
Abstract: The current trends in stimulated Brillouin scattering and optical phase conjugation are overviewed. This report is formed by the selected papers presented in the “Fifth International Workshop on stimulated Brillouin scattering and phase conjugation 2010” in Japan. The nonlinear properties of phase conjugation based on stimulated Brillouin scattering and photo-refraction can compensate phase distortions in the high power laser systems, and they will also open up potentially novel laser technologies, e.g., phase stabilization, beam combination, pulse compression, ultrafast pulse shaping, and arbitrary waveform generation.

33 citations

Journal ArticleDOI
TL;DR: The results suggest that the polarization vortex evaluates the global polarization property of the closed-loop electron that plays an important role in the quantum correlation phenomena such as the Aharonov-Bohm effect.
Abstract: We evaluate the quasi-one-dimensional (1D) electron dynamics in a NbSe3 ring crystal using polarization vortex pulses with various azimuthal distributions. The single particle relaxation component reveals a large anisotropy on the crystal, indicating that the electrons in the ring maintain their 1D character. The results also suggest that the polarization vortex evaluates the global polarization property of the closed-loop electron that plays an important role in the quantum correlation phenomena such as the Aharonov-Bohm effect.

32 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: The authors survey the steady refinement of techniques used to create optical vortices, and explore their applications, which include sophisticated optical computing processes, novel microscopy and imaging techniques, the creation of ‘optical tweezers’ to trap particles of matter, and optical machining using light to pattern structures on the nanoscale.
Abstract: Thirty years ago, Coullet et al. proposed that a special optical field exists in laser cavities bearing some analogy with the superfluid vortex. Since then, optical vortices have been widely studied, inspired by the hydrodynamics sharing similar mathematics. Akin to a fluid vortex with a central flow singularity, an optical vortex beam has a phase singularity with a certain topological charge, giving rise to a hollow intensity distribution. Such a beam with helical phase fronts and orbital angular momentum reveals a subtle connection between macroscopic physical optics and microscopic quantum optics. These amazing properties provide a new understanding of a wide range of optical and physical phenomena, including twisting photons, spin-orbital interactions, Bose-Einstein condensates, etc., while the associated technologies for manipulating optical vortices have become increasingly tunable and flexible. Hitherto, owing to these salient properties and optical manipulation technologies, tunable vortex beams have engendered tremendous advanced applications such as optical tweezers, high-order quantum entanglement, and nonlinear optics. This article reviews the recent progress in tunable vortex technologies along with their advanced applications.

1,016 citations

Journal ArticleDOI
TL;DR: In this paper, the angular momentum of light can be described by positions on a higher-order Poincare sphere, where superpositions of spin and orbital angular momentum states give rise to laser beams that have many applications.
Abstract: The angular momentum of light can be described by positions on a higher-order Poincare sphere, where superpositions of spin and orbital angular momentum states give rise to laser beams that have many applications, from microscopy to materials processing. Many techniques exist to create such beams but none so far allow their creation at the source. Here we report on a new class of laser that is able to generate all states on the higher-order Poincare sphere. We exploit geometric phase control inside a laser cavity to map polarization to orbital angular momentum, demonstrating that the orbital angular momentum degeneracy of a standard laser cavity may be broken, producing pure orbital angular momentum beams, and that generalized vector vortex beams may be created with high purity at the source. This work paves the way to new lasers for structured light based on intracavity geometric phase control. By exploiting geometric phase control inside a laser cavity to map polarization to orbital angular momentum, a new class of laser that is able to generate all states on the higher-order Poincare sphere is reported.

466 citations

Journal Article
TL;DR: A novel method by C. Zhou and R. Betti to assemble and ignite thermonuclear fuel is presented, which features a hot-spot pressure greater than the surrounding dense fuel pressure and requires a lower energy threshold than the conventional isobaric one.
Abstract: A novel method by C. Zhou and R. Betti [Bull. Am. Phys. Soc. 50, 140 (2005)] to assemble and ignite thermonuclear fuel is presented. Massive cryogenic shells are first imploded by direct laser light with a low implosion velocity and on a low adiabat leading to fuel assemblies with large areal densities. The assembled fuel is ignited from a central hot spot heated by the collision of a spherically convergent ignitor shock and the return shock. The resulting fuel assembly features a hot-spot pressure greater than the surrounding dense fuel pressure. Such a nonisobaric assembly requires a lower energy threshold for ignition than the conventional isobaric one. The ignitor shock can be launched by a spike in the laser power or by particle beams. The thermonuclear gain can be significantly larger than in conventional isobaric ignition for equal driver energy.

365 citations

Journal ArticleDOI
TL;DR: In this article, the fundamental concepts of vector beams, summarise the various approaches to control them in the laboratory, and give a concise overview of the many applications they have spurned.
Abstract: Vector beams, and in particular vector vortex beams, have found many applications in recent times, both as classical fields and as quantum states. While much attention has focused on the creation and detection of scalar optical fields, it is only recently that vector beams have found their place in the modern laboratory. In this review, we outline the fundamental concepts of vector beams, summarise the various approaches to control them in the laboratory, and give a concise overview of the many applications they have spurned.

294 citations

Journal ArticleDOI
TL;DR: In this paper, the authors summarized different approaches for optical vortex generation by discrete components and laser cavities, and highlighted the independent operation of these two different phases which leads to a multifunctional optical vortex beam generation and independent spin-orbit interaction.
Abstract: Abstract This article reviews recent progress leading to the generation of optical vortex beams. After introducing the basics of optical vortex beams and their promising applications, we summarized different approaches for optical vortex generation by discrete components and laser cavities. We place particular emphasis on the recent development of vortex generation by the planar phase plates, which are able to engineer a spiral phasefront via dynamic or geometric phase in nanoscale, and highlight the independent operation of these two different phases which leads to a multifunctional optical vortex beam generation and independent spin-orbit interaction. We also introduced the recent progress on vortex lasing, including vortex beam generation from the output of bulk lasers by modification of conventional laser cavities with phase elements and from integrated on-chip microlasers. Similar approaches are also applied to generate fractional vortex beams carrying fractional topological charge. The advanced technology and approaches on design and nanofabrications enable multiple vortex beams generation from a single device via multiplexing, multicasting, and vortex array, open up opportunities for applications on data processing, information encoding/decoding, communication and parallel data processing, and micromanipulations.

214 citations