Quasi-phase-matched parametric fluorescence in room-temperature lithium tantalate waveguides

Area of Science:

• Nonlinear optics
• Materials science

Background:

• Parametric fluorescence is a key phenomenon in nonlinear optics.
• Lithium tantalate (LT) and lithium niobate (LN) are widely used ferroelectric crystals for nonlinear optical devices.
• Waveguide structures enhance light-matter interactions for efficient nonlinear processes.

Purpose of the Study:

• To report the first observation of quasi-phase-matched parametric fluorescence in lithium tantalate waveguides.
• To investigate the performance of lithium tantalate waveguides for parametric fluorescence generation.
• To compare the efficiency of lithium tantalate with lithium niobate for this application.

Main Methods:

• Fabrication of lithium tantalate waveguides.
• Utilizing quasi-phase-matching (QPM) technique for parametric fluorescence.
• Pumping the waveguides with wavelengths ranging from 805 to 845 nm.
• Measuring the generated fluorescence power in the 1.2-2.3-microm region.

Main Results:

• Successful generation of quasi-phase-matched parametric fluorescence in lithium tantalate waveguides at ambient temperature.
• Observed signal fluorescent power up to 7 pW with 70 mW guided pump power.
• Demonstrated a strong dependence of signal fluorescent power on the proton concentration in the waveguide.
• Achieved an efficiency one order of magnitude lower than that measured with lithium niobate guides.

Conclusions:

• Lithium tantalate waveguides can support quasi-phase-matched parametric fluorescence.
• Proton concentration is a critical factor for optimizing fluorescence efficiency in these waveguides.
• Further optimization is needed to match the efficiency of lithium niobate for practical applications.