Second harmonic generation of visible vortex laser based on a waveguide-grating emitter in LBO

Area of Science:

• Integrated optics
• Nonlinear optics
• Laser physics

Background:

• Vortex laser beams possess unique orbital angular momentum properties.
• Generating visible vortex lasers efficiently is crucial for applications in optical manipulation and information processing.
• Integrated photonic devices offer miniaturization and enhanced control over light properties.

Purpose of the Study:

• To propose and demonstrate a practical solution for visible vortex laser emission at 532 nm.
• To investigate the fabrication and performance of a waveguide-grating structure for nonlinear vortex beam generation.
• To analyze the impact of femtosecond laser direct writing on crystal properties and device functionality.

Main Methods:

• Fabrication of a waveguide-grating structure in an LBO crystal using femtosecond laser direct writing (FsLDW).
• Characterization of FsLDW-induced localized crystalline damage using confocal micro-Raman spectroscopy.
• Optical characterization of guiding properties, second harmonic generation (SHG) performance, and vortex laser generation at 532 nm under 1064 nm excitation.

Main Results:

• Successful fabrication of an integrated waveguide-grating structure capable of visible vortex laser emission.
• Demonstration of efficient second harmonic generation (SHG) for 532 nm vortex beam production.
• Systematic study confirming the guiding and nonlinear optical properties of the hybrid structure.

Conclusions:

• The proposed waveguide-grating emitter fabricated by FsLDW is a reliable design for nonlinear vortex beam generation.
• This integrated approach holds significant promise for advancing compact and efficient vortex laser sources.
• The findings pave the way for novel applications in integrated nonlinear photonics.