Surface-emitted terahertz-wave difference-frequency generation in two-dimensional periodically poled lithium niobate

Area of Science:

• Optics and Photonics
• Materials Science
• Solid-State Physics

Background:

• Terahertz (THz) wave generation is crucial for various spectroscopic and imaging applications.
• Periodically poled lithium niobate (PPLN) is a key material for nonlinear optical frequency conversion.
• Achieving efficient and tunable THz wave generation remains a significant challenge.

Purpose of the Study:

• To demonstrate surface-emitted THz wave difference-frequency generation using 2D PPLN.
• To achieve tunable THz wave generation with a specific frequency range and bandwidth.
• To investigate the directional properties of the generated THz waves.

Main Methods:

• Utilized two-dimensional (2D) periodically poled lithium niobate (PPLN) crystals.
• Employed orthogonal periodic structures to compensate for phase mismatch.
• Implemented surface-emitted difference-frequency generation technique.
• Used two PPLN crystals to generate tunable THz waves.

Main Results:

• Successfully demonstrated surface-emitted THz wave generation from 2D PPLN.
• Achieved tunable THz wave generation in the 1.5-1.8 THz range with a 10-GHz bandwidth.
• Observed simultaneous THz wave generation in two opposite directions.
• Confirmed the effectiveness of orthogonal structures in phase mismatch compensation.

Conclusions:

• 2D PPLN is a viable material for efficient surface-emitted THz wave generation.
• The demonstrated method allows for tunable THz wave output.
• Bidirectional THz wave emission indicates potential for increased output power.