Resonantly enhanced terahertz four-wave mixing in fluorides

TL;DR

This paper demonstrates resonantly enhanced terahertz four-wave mixing in fluoride crystals, enabling efficient conversion of THz signals into the optical domain for sensing and spectroscopy applications.

Contribution

It reports the observation of resonantly amplified THz four-wave mixing in CaF$_2$, BaF$_2$, and MgF$_2$, highlighting a new method for THz-to-optical conversion.

Findings

Resonant enhancement observed near 400 nm wavelength.

Effective THz-to-optical conversion demonstrated in fluoride crystals.

Potential applications in THz sensing and spectroscopy.

Abstract

Converting a THz signal into the optical domain is of great interest for THz sensing and spectroscopy. Here intense broadband THz pulses with a central frequency of $\Omega$$_{THz}$ are mixed with an optical pump at $\omega$$_p$ and a signal is observed at a wavelength of $\omega$$_s$ = 2($\omega$$_p$ - $\Delta\omega$$_p$) - $\Omega_{THz}$ with the detuning $\omega$$_p$ - $\Delta\omega$$_p$ being due to pump pulse spectral broadening. The observed THz-FWM signal close to 400 nm is shown to result from a resonantly amplified four-wave mixing in CaF$_2$, BaF$_2$ and MgF$_2$.