We study the fundamental molecular dynamics of liquids in the bulk, using advanced nonlinear spectroscopic techniques. By using high-field THz pulses of ~3MV/cm field-strength we are able to excite the rotational motions of liquids residing in the low frequencies of the electromagnetic spectrum and then either measure the induced transient birefridgence by an optical Raman pulse in a Terahertz Kerr effect (TKE) configuration or measure the effect of the initial coupling to the intermolecular translational modes, residing at higher frequencies by an ultrabroadband THz-probe pulse, covering frequencies up to ~15THz, using the novel THz spintronic emitter (STE). Lastly, we are now setting up an ultrabroadband 2D-THz setup for mapping-out the energy transfer pathways and couplings between the low frequency motions of liquids.

Schematic representation of: a) THz-pump/THz-probe, where the narrow-band pulse (LiNiO3) excites the rotational motions of water and the time delayed ultrabroadband pulse (STE) records the resulting changes in the translational modes. b) The ultrabroadband 2D-THz experiment will show us if and how the low frequency intermolecular modes of water are coupled.