Ultrafast dynamics observed at low energies carry insightful information about the complex many-body interactions in solid-state materials. Here

we present a highly sensitive and robust setup for asymmetric 2-dimensional spectroscopy performing 2-pulse visible excitation combined with probing in the 15- to 35-THz frequency range. This experimental setup is ideal for targeting the interplay of high- and low-energy correlations in functional materials with femtosecond temporal and millielectronvolt energy resolution. In addition

the sub-cycle field resolution of mid-infrared pulses enables tracking nonthermal interactions in the complex dielectric function. Prototypical measurements benchmark ultrafast carrier dynamics in thin-film graphite

showing in detail the interplay of direct and indirect optical transitions in the transient excited state. We further investigate the photo-induced collapse of the superconducting condensate in the high-temperature superconductor BiSrCaCuO at energies resonant to the optical bandgap

revealing a nontrivial instantaneous nonlinearity related to the excited quasiparticles in the material. Optical pump–terahertz probe experiments build the foundation for this evolutionary step in 2-dimensional spectroscopy as well as for terahertz 4-wave mixing with resonant driving and readout of the superconducting state. Our results offer exciting perspectives in the study of strong correlations and enable precise investigations of nontrivial many-body interactions in few-layer samples and nanostructures.