Progress toward an efficient, uniformly scalable lithium niobate terahertz pulse source

Area of Science:

• Nonlinear optics
• Terahertz (THz) generation

Background:

• Compact and efficient THz sources are crucial for various applications.
• Previous tilted-pulse-front-pumped (TPFP) THz sources faced limitations in efficiency and scalability.

Purpose of the Study:

• To develop a compact, imaging-free, and scalable TPFP THz source.
• To characterize THz generation efficiency based on slab thickness and pump intensity.
• To investigate the impact of microstructure quality on THz generation.

Main Methods:

• Utilized a nonlinear echelon slab for THz generation.
• Performed systematic characterization of THz generation efficiency.
• Investigated the influence of surface roughness on efficiency.
• Developed a theoretical model for THz generation.

Main Results:

• Achieved a THz generation efficiency of ~0.085%, a 2.8x improvement over previous results.
• Demonstrated that surface roughness negatively impacts efficiency by reducing diffraction and increasing beam divergence.
• The theoretical model accurately predicted experimental outcomes.

Conclusions:

• The nonlinear echelon slab is a promising platform for compact and efficient THz sources.
• Refining microstructure quality is key to unlocking significantly higher THz generation efficiencies (predicted >0.65% at room temperature).
• The developed theoretical model provides a pathway for optimizing future THz source designs.