Versatile terahertz spectroscopy platform for quantum materials research

Terahertz (THz) spectroscopy bridges the gap between electronics and optics, enabling contact-free measurements of complex refractive index, frequency-dependent conductivity, and carrier dynamics across 0.1-10 THz, a spectral window encompassing phonons, magnons, and low-energy electronic excitations such as Dirac cones and flat bands. In particular, THz time-domain spectroscopy (THz-TDS) provides direct access to these properties and reveals scattering mechanisms involving electronic, lattice, and spin degrees of freedom. When combined with an optical pump pulse in optical-pump/THz-probe (OPTP) experiments, the technique captures photoconductivity and photoinduced phase transitions, offering insight into sub-picosecond quasiparticle dynamics and metastable phases.

We present a versatile THz spectroscopy platform featuring a diffraction-limited THz beam profile, field strengths exceeding 100 kV/cm, and an integrated helium cryostat for temperature-dependent studies. Our platform is able to perform THz-TDS and OPTP measurements on a wide range of quantum materials, including correlated, superconducting, or topological systems. Moreover, its high THz field strength enables the direct excitation of resonances at THz frequencies, which will be explored in future experiments. We present preliminary results on technologically relevant quantum materials to highlights the setup’s design, performance, and preliminary results that demonstrate its capabilities.