Flat liquid jet as a highly efficient source of terahertz radiation

Area of Science:

• Physics
• Optics
• Materials Science

Background:

• Polar liquids strongly absorb terahertz waves, limiting their use in terahertz sources.
• Flowing liquid media offer advantages like higher damage thresholds and efficient ionization compared to solids and gases.

Purpose of the Study:

• To investigate efficient terahertz radiation generation in flat liquid jets.
• To explore the influence of medium parameters on terahertz emission.
• To optimize excitation conditions for enhanced terahertz output.

Main Methods:

• Systematic experimental study of terahertz emission from flat liquid jets.
• Sub-picosecond single-color optical excitation.
• Theoretical prediction and experimental confirmation of optimal pump pulse duration.
• Analysis of medium parameters: molecular density, ionization energy, and linear absorption.

Main Results:

• Demonstrated efficient terahertz generation in liquid jets.
• Identified quasi-quadratic dependence of terahertz energy on optical excitation pulse energy.
• Determined optimal pump pulse duration based on jet thickness.
• Achieved optical-to-terahertz energy conversion efficiency exceeding 0.05%.

Conclusions:

• Flowing liquid jets are a viable medium for efficient terahertz radiation generation.
• The study provides a pathway for developing new, efficient terahertz sources.
• Results are comparable to established methods like optical rectification and air filamentation.