Multi-wavelength applicable waveguide vortex beam generator in lithium niobate processed by femtosecond laser direct writing
Waveguide
Optical vortex
DOI:
10.1364/ol.562226
Publication Date:
2025-05-29T12:00:10Z
AUTHORS (6)
ABSTRACT
In this Letter, we report a micrometer-scale customized guiding device designed for generating vortex beams in lithium niobate (LN) crystals processed by femtosecond laser direct writing (FLDW) technology. Confocal-Raman microscope measurements were skillfully utilized to thoroughly clarify the microscopic mechanisms involved in the laser-induced alteration of the crystal lattice and the formation of various waveguide types. Finite-difference time-domain (FDTD) simulations confirm that the designed array of stable-optimized Type-I waveguides with stepped length gradients demonstrates selective orbital angular momentum (OAM) excitation under multi-wavelength illumination and the wavelength–OAM correlation governed by the waveguide length-dependent phase accumulation mechanism. The wavelength-dependent vortex generation was experimentally characterized using an end-coupled interrogation setup with continuous laser sources at 1064 nm and 532 nm, verifying the structural response to wavelength variations. Our results vividly demonstrate that the multi-waveguide hybrid structure within lithium niobate crystals has remarkable potential for applications in vortex beam generators functioning at different wavelengths.
SUPPLEMENTAL MATERIAL
Coming soon ....
REFERENCES (38)
CITATIONS (0)
EXTERNAL LINKS
PlumX Metrics
RECOMMENDATIONS
FAIR ASSESSMENT
Coming soon ....
JUPYTER LAB
Coming soon ....