Milliwatt-order blue-light generation in a periodically domain-inverted LiTaO(3) waveguide

Area of Science:

• Nonlinear optics
• Materials science
• Photonics

Background:

• Second-harmonic generation (SHG) is crucial for frequency conversion in photonics.
• Lithium tantalate (LiTaO3) and lithium niobate (LiNbO3) are key materials for nonlinear optical devices.
• Quasi-phase-matching (QPM) using periodically poled structures enhances SHG efficiency.

Purpose of the Study:

• To characterize a novel quasi-phase-matched second-harmonic generation device in LiTaO3.
• To evaluate the performance of a device featuring a periodically domain-inverted region and a proton-exchanged channel waveguide.
• To compare the device's temperature bandwidth with similar devices in LiNbO3.

Main Methods:

• Fabrication of a QPM SHG device in LiTaO3 with a periodically domain-inverted region.
• Integration of a proton-exchanged channel waveguide for light confinement.
• Characterization of the generated blue light power and wavelength.
• Measurement of the temperature bandwidth for full width at half maximum (FWHM) power.

Main Results:

• Achieved a blue-light output power of 2.4 mW at a 424-nm wavelength.
• Observed a temperature bandwidth of approximately 3 °C-cm (FWHM), which is three times wider than in LiNbO3 devices.
• Demonstrated the potential for diffraction-limited focusing of the generated blue light.

Conclusions:

• The developed LiTaO3 SHG device exhibits enhanced temperature stability for efficient blue light generation.
• The device's performance, particularly its wider temperature bandwidth, makes it a promising alternative to LiNbO3-based devices.
• The capability for diffraction-limited focusing opens possibilities for advanced photonic applications requiring high-quality blue light sources.