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Chinese Optics Letters

Chinese Journal of Lasers B

High Power Laser Science and Engineering
Frontiers of Optoelectronics
Photonics Research

Journal of Innovative Optical Health Sciences

International Journal of Extreme Manufacturing

Journal of Semiconductors

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Reviews

Cylindrical vector beams and vortex beams, two types of typical singular optical beams characterized by axially symmetric polarization and helical phase front, possess the unique focusing property and the ability of carrying orbital angular momentum. We discuss the formation mechanisms of such singular beams in few-mode fibers under the vortex basis and show recent advances in generating techniques that are mainly based on long-period fiber gratings, mode-selective couplers, offset-spliced fibers, and tapered fibers. The performances of cylindrical vector beams and vortex beams generated in fibers and fiber lasers are summarized and compared to give a comprehensive understanding of singular beams and to promote their practical applications.
2021, 3(1): 014002
Letters

Nonlinear holography has been identified as a vital platform for optical multiplexing holography because of the appearance of new optical frequencies. However, due to nonlinear wave coupling in nonlinear optical processes, the nonlinear harmonic field is coupled with the input field, laying a fundamental barrier to independent control of the interacting fields for holography. We propose and experimentally demonstrate high-dimensional orbital angular momentum (OAM) multiplexing nonlinear holography to overcome this problem. By dividing the wavefront of the fundamental wave into different orthogonal OAM channels, multiple OAM and polarization-dependent holographic images in both the fundamental wave and second-harmonic wave have been reconstructed independently in the spatial frequency domain through a type-II second harmonic generation process. Moreover, this method can be easily extended to cascaded χ2 nonlinear optical processes for multiplexing in more wavelength channels, leading to potential applications in multicasting in optical communications, multiwavelength display, multidimensional optical storage, anticounterfeiting, and optical encryption.
2021, 3(1): 015001
Early Posting

We propose a design of single-mode orbital angular momentum (OAM) beam laser with high direct-modulation bandwidth. It’s a microcylinder/microring cavity interacted with two types of second-order gratings: the complex top grating containing the real part and the imaginary part modulation and the side grating. The side grating etched on the periphery of the microcylinder/microring cavity can select a whispering gallery mode with a specific azimuthal mode number. While the complex top gratings can scatter the lasing mode with travelling-wave pattern vertically. With the cooperation of the gratings, the laser works with a single mode and emits radially polarized OAM beams. With an asymmetrical pad metal on the top of the cavity, the OAM on-chip laser can firstly be directly modulated with electrical pumping. Due to the small active volume, the laser with low threshold current is predicted to have a high direct modulation bandwidth about 29 GHz with the bias current of ten times the threshold from the simulation. The semiconductor OAM laser can be rather easily realized at different wavelengths such as the O band, C band and L band.
Chinese Optics Letters
2021, 19(8):
Special Issue on Lithium Niobate Based Photonic Devices

Based on nonlinear wave mixing, we experimentally propose a scheme for directly generating optical orbital angular momentum (OAM) by a spirally structured fundamental wave interacting with a nonlinear medium, in which the nonlinear susceptibilities are homogenous. In the experiment, the second-harmonic generation of a fundamental wave carrying positive (negative) integers and fractional OAM states was investigated. This study presents a convenient approach for dynamic control of OAM of vortex beams, which may feature their applications in optical manipulation and optical communication.
Chinese Optics Letters
2021, 19(6): 060005
Physical Optics

The evolution of the spin density vectors (SDVs) is studied in a strongly focused composite field. It is found that the SDVs can be spiral along the propagation axis, and they are perpendicular to the $ys$ direction on the $ys$ axis. This behavior is governed by the Gouy phase difference between the field polarization components. The $60°$ rotation of the spatial distribution of the transverse SDVs is also generated, which is found to be controlled by the Gouy phase difference between the field orbital angular momentum modes. Additionally, the spin density singularities are observed in the evolution of the SDVs.
Chinese Optics Letters
2021, 19(2): 022601
Early Posting

Orbital angular momentum (OAM) is a fundamental physical characteristic to describe laser fields with a spiral phase structure. Vortex beams carrying OAMs have attracted more and more attention in recent years. However, the wavefront of OAM light would be destroyed when it passes through scattering media. Here, based on the feedback-based wavefront shaping method, we reconstitute OAM wavefront behind strong scattering media. The intensity of light with desired OAM states is enhanced to 150 times. This study provides a method to manipulate OAMs of scattered light, and is of great significance for OAM optical communication and imaging to overcome complex environment interference.
Chinese Optics Letters
2021, 19(10):

2020, 57(5): 050008

2020, 49(6): 0606002

2020, 47(5): 0500013

2020, 47(4): 0412001
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