Terahertz generation by optical rectification in chalcopyrite crystals ZnGeP₂, CdGeP₂ and CdSiP₂

Area of Science:

• Solid State Physics
• Optoelectronics
• Nonlinear Optics

Background:

• Terahertz (THz) radiation generation is crucial for various spectroscopic and imaging applications.
• Chalcopyrite crystals offer unique nonlinear optical properties for THz emission.

Purpose of the Study:

• To investigate optical rectification of near-infrared laser pulses for broadband THz radiation generation.
• To characterize THz emission from CdGeP2, ZnGeP2, and CdSiP2 crystals.
• To determine nonlinear coefficients of these chalcopyrite crystals.

Main Methods:

• Optical rectification of linearly polarized near-infrared laser pulses (0.8 eV - 1.55 eV).
• Characterization of THz emission bandwidth (~2.5 THz) from 0.5 mm (110)-cut crystals.
• Analysis of pump-intensity dependence to extract nonlinear coefficients.

Main Results:

• Broadband THz radiation was successfully generated in CdGeP2, ZnGeP2, and CdSiP2.
• CdGeP2 exhibited the strongest emission at telecom wavelengths (around 1.55 eV).
• CdSiP2 generally demonstrated the strongest overall THz emission.
• Nonlinear coefficients were determined for each crystal.

Conclusions:

• Chalcopyrite crystals are effective materials for generating broadband THz radiation via optical rectification.
• CdGeP2 and CdSiP2 are promising candidates for THz sources, particularly for telecommunication applications.
• The study provides valuable nonlinear optical coefficients for these materials.