Widely tunable cavity-enhanced ultrafast spectroscopy and the dynamics of hydrogen bond networks.*

Ultrafast optical spectroscopy methods, such as transient absorption spectroscopy and 2D spectroscopy, are widely used across many disciplines. However, these techniques are typically restricted to optically thick samples, such as solids and liquid solutions. In previous work [Reber et al. Optica 3, 311 (2016)], using frequency comb lasers and resonant optical cavities, we have demonstrated the extension of all-optical ultrafast spectroscopy methods to dilute molecular beams and recorded transient absorption signals with detection limits as low as ΔOD = 2×10^-10. In this talk I will discuss our progress in developing widely tunable cavity-enhanced ultrafast spectrometers operating from the ultraviolet to the mid-infrared and their application to the ultrafast dynamics of elementary hydrogen bond networks.