Milliwatt-class broadband THz source driven by a 112 W, sub-100 fs thin-disk laser.

Area of Science:

• Physics
• Optics
• Materials Science

Background:

• Terahertz (THz) spectroscopy is crucial for material analysis but limited by low signal-to-noise ratios.
• Existing THz sources often require complex amplification systems, hindering practical applications.

Purpose of the Study:

• To demonstrate a high-repetition-rate, single-cycle THz source with high average power.
• To achieve this using optical rectification in Gallium Phosphide (GaP) without an amplifier.

Main Methods:

• Utilized an amplifier-free, nonlinearly compressed mode-locked thin-disk oscillator based on Yb:YAG.
• Generated 8.4 µJ pulses with 88 fs duration at a 13.4 MHz repetition rate.
• Employed optical rectification in GaP to generate THz radiation.

Main Results:

• Achieved a maximum average THz power of 1.35 mW at a center frequency of 2 THz.
• The driving pulses had 112 W average power and 80 MW peak power.
• This represents the highest average power reported for optical rectification in GaP.

Conclusions:

• The demonstrated THz source offers significant performance improvements over existing technologies.
• This high-power THz source is highly suitable for advancing linear THz time-domain spectroscopy.
• The findings pave the way for more sensitive and efficient THz spectroscopy applications.