Single-cycle, 643 mW average power terahertz source based on tilted pulse front in lithium niobate

Area of Science:

• Terahertz (THz) Science and Technology
• Nonlinear Optics
• Laser Physics

Background:

• High-power terahertz (THz) sources are crucial for advanced spectroscopic techniques.
• Existing THz sources often face limitations in average power and repetition rate, hindering experiments.
• Optical rectification in lithium niobate is a promising method for THz generation.

Purpose of the Study:

• To demonstrate the highest average power from a laser-driven single-cycle THz source to date.
• To investigate the impact of repetition rate on THz generation efficiency at high average power.
• To establish a benchmark for high-average-power THz time-domain spectroscopy systems.

Main Methods:

• Utilized optical rectification in a tilted pulse front geometry within cryogenically cooled lithium niobate.
• Employed a commercially available 500 W ultrafast thin-disk ytterbium (Yb) amplifier as the pump source.
• Studied repetition rate-dependent effects at 100 kHz and 40 kHz.

Main Results:

• Achieved record-breaking average power for a laser-driven single-cycle THz source.
• Demonstrated multi-100 mW average power at high repetition rates (100 and 40 kHz).
• Identified distinct optimal fluence conditions for efficient THz conversion at different repetition rates.

Conclusions:

• The developed THz source offers a unique combination of high THz pulse energy and high repetition rate.
• This system significantly reduces measurement times for nonlinear THz spectroscopy experiments.
• Represents a significant advancement for high-average-power THz time-domain spectroscopy driven by ultrafast Yb lasers.