Third-order orbital angular momentum pulse generation from a passively Q-switched fiber laser
We propose and demonstrate an all-fiber passively Q-switched laser generating a third-order orbital angular momentum (OAM) pulse by introducing a few-mode long-period fiber grating (LPFG) into the laser cavity. The LPFG with asymmetric cross structure and strong refractive index modulation overcomes...
Main Authors: | , , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Optica Publishing Group (formerly OSA)
2022
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Subjects: | |
Online Access: | View Fulltext in Publisher |
Summary: | We propose and demonstrate an all-fiber passively Q-switched laser generating a third-order orbital angular momentum (OAM) pulse by introducing a few-mode long-period fiber grating (LPFG) into the laser cavity. The LPFG with asymmetric cross structure and strong refractive index modulation overcomes the coupling issue between the fundamental and the third-azimuthal-order (LP31 or OAM3) modes and realizes their direct conversion. A homemade graphene-based saturable absorber is used to realize Q-switched operation. The laser operates at a center wavelength of 1548.2nm, with a 3 dB spectral bandwidth of 0.4nm, and the OAM+3 and OAM−3 beams can achieve the purity of 90.0% and 90.2%, respectively. This all-fiber Q-switched laser has simple and compact structure and high purity of OAM±3 beams, which has potential applications in the fields of optical tweezers and material processing. © 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement Journal © 2022 |
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Physical Description: | 10 |
ISBN: | 10944087 (ISSN) |
DOI: | 10.1364/OE.454147 |