Technique Development – We create novel tools for ultrafast spectroscopy. This involves developing new THz sources such as organic nonlinear crystals for THz generation and optimized schemes of plasma generation of THz. We also are pushing the limits of high-speed data acquisition with single-shot probing measurements.
Structural and Vibrational Control – We use high-field THz radiation to excite vibrations and drive atoms in a crystalline lattice far from equilibrium. We excite phonon modes in solids to extreme amplitudes, allowing us to investigate anharmonic coupling between different modes, and to even extract the shape of the potential energy surface along the relevant vibrational coordinates. Early results have shown that experimental determination of the PES is possible [Dastrup et al. App. Phys. Lett. 110, 162901 (2017).], and new preliminary results are revealing the intricacies of anharmonic coupling by exciting and probing multiple vibrational degrees of freedom simultaneously.
THz electronics – A host of electronic devices operate due to electric field induced carrier multiplication in the semiconductor core of key components. With the goal to push device operation to the highest speeds, understanding field-induced electronic excitation at terahertz (THz) frequencies is crucial. For fundamental studies using THz to induce high-speed carrier multiplication, extremely high electric field strengths are needed. We utilize strong THz pulses in conjunction with meta-material structures to study excited electron dynamics in semiconductors and gain key information for developing future high-speed electronics.