Controlled higher-order transverse mode conversion from a fiber laser by polarization manipulation

Abstract

We report a vectorial fiber laser with controlled transverse mode conversion by intra-cavity polarization manipulation. By combining a q-plate and two quarter-wave plates (QWPs), we can generate a switchable polarization state output represented by the higher-order Poincaré sphere (l = +1, l = −1), and distinguish the fourfold degenerate LP11 mode. The four transverse vector modes can be obtained and switched in a flexible way, and the slope efficiency of the fiber laser can reach up to 39.4%. This compactness, high efficiency, and switchable operation potential will benefit a range of applications, such as materials processing, particle manipulation, etc.

A review of complex vector light fields and their applications

“…demonstrated; the reader is referred to review papers on the topic [130][131][132]. On the equator, one finds the cylindrical vector vortex beams, and these special cases have been extensively study in the context of intra-cavity generation [132,133], with recent advances mostly in fiber lasers [134][135][136][137][138][139][140] with some interesting solutions making use of metamaterials [141] (shown in figure 17) and saturable absorbers [142]. Recently, a notable advance was made in the ability to produce all states on the HOPS, including the scalar OAM modes, all from the same laser [143].…”

Generation of polarization and phase singular beams in fibers and fiber lasers

“…Simultaneously, various techniques and elements were developed to generate CVBs and VBs. For instance, spatial light modulators, 21,22 axial birefringent components, [23][24][25] specially designed laser cavities, [26][27][28] interferometric methods, [29][30][31][32] and nanostructured holograms 33 have been proposed to convert Gaussian beams into CVBs or to directly emit CVBs. At the same time, photopatterning of liquid crystals, 34,35 spiral phase plates, 36,37 computer generated holograms, 38 microresonators or subwavelength gratings, 39 helically twisted fibers, 40 as well as plasmonic metasurfaces [41][42][43][44] were developed to generate VBs.…”

Effectively Identifying the Topological Charge and Polarization Order of Arbitrary Singular Light Beams Based on Orthogonal Polarization Separating

“…These beams are also called cylindrical vector vortex beams (CVVBs) and have attracted extensive attentions in optical manipulation [32]- [35]. Plenty of approaches have been proposed to generate singular beams [36]- [46]. However, apart from creating high-quality singular beams, it is also crucial to effectively identify their topological charge and polarization order.…”