Peak emission of terahertz waves from (110)-oriented ZnTe by interacting phase-matched phonon resonances

Abstract

We demonstrate the measurement and assignment of phonon resonances responsible for observed peak emission of terahertz (THz) waves from (110)-ZnTe. We show that optical rectification in ZnTe using femtosecond pulses centered at 790 nm involves phase-matched fundamental and difference-phonon resonances at 1.63, 1.95, 2.25, and 2.55 THz, which produce a THz peak at 2.1 THz and damped oscillations for 6 ps after the main THz pulse. Phonon resonances in ZnTe have been measured and assigned by mathematical modeling and terahertz time-domain spectroscopy (THz-TDS) over the range 0.1–3 THz. The refractive index and optical absorption coefficient of ZnTe have also been extracted from the measured THz-TDS data. The results give greater insight into the dynamics of ZnTe for ultrafast optoelectronic systems.