Temperature-independent non-linear terahertz transmission by liquid water

Abstract

Liquid water is one of the most studied substances, yet many of its properties are difficult to rationalize. The uniqueness of water is rooted in the dynamic network of hydrogen-bonded molecules with relaxation time constants of about one picosecond. Terahertz fields oscillate on a picosecond timescale and are inherently suited to study water. Recent advances in non-linear terahertz spectroscopy have revealed large signals from water, which have been interpreted with different, sometimes competing, theoretical models. Here we show that the non-linear transmission of liquid water at ~1 THz is equal at 21 °C and 4 °C, thus suggesting that the most appropriate microscopic models should depend weakly on temperature. Among the different mechanisms proposed to date, the resonant reorientation of hydrogen-bonded water molecules might be the most appropriate to describe all of the currently available experimental results.

References in corpus (8)

• Single-cycle THz pulses with amplitudes exceeding 1 MV/cm generated by optical rectification in LiNbO3
• Terahertz Kerr effect
• Electromagnetic-radiation absorption of water
• The hydrogen bond network of water supports propagating optical phonon-like modes
• The origin of the Debye relaxation in liquid water and fitting the high frequency excess response
• High Kerr nonlinearity of water in THz spectral range
• Field-Induced Tunneling Ionization and Terahertz-Driven Electron Dynamics in Liquid Water
• Terahertz Polaron Oscillations of Electrons Solvated in Liquid Water