Intra-pulse difference frequency generation in ZnGeP₂ for high-frequency terahertz radiation generation

Area of Science:

• Nonlinear optics
• Terahertz (THz) science and technology
• Solid-state physics

Background:

• Chalcopyrite crystals are effective sources for mid-infrared light.
• High-frequency terahertz (THz) electric fields are crucial for various scientific applications.
• Previous methods have limitations in generating phase-resolved THz fields.

Purpose of the Study:

• To demonstrate the generation of phase-resolved terahertz electric fields using a chalcopyrite crystal.
• To explore the potential of ZnGeP2 for high-frequency THz generation.
• To achieve efficient intra-pulse difference frequency generation in the THz range.

Main Methods:

• Employed intra-pulse difference frequency generation within a chalcopyrite (110) ZnGeP2 crystal.
• Utilized excitation electric field pulses with polarizations along both ordinary and extraordinary crystal axes for phase-matching.
• Analyzed the generated terahertz spectrum to determine power and frequency range.

Main Results:

• Successfully generated phase-resolved terahertz electric field pulses.
• Observed maximum spectral power at 24.5 THz, consistent with phase-matching calculations.
• Achieved terahertz generation across a wide spectral range of 23-30 THz.

Conclusions:

• This study represents the first use of a chalcopyrite ZnGeP2 crystal for generating phase-resolved high-frequency terahertz electric fields.
• ZnGeP2 is a promising material for efficient THz generation.
• The demonstrated technique offers a new pathway for producing tailored THz electric fields.