Integrated Nonlinear Photonics for Terahertz Spectroscopy of Quantum Materials

The study of quantum materials in the terahertz (THz) range is of particular interest for probing important quantum excitations that naturally occur in that band. However, bulk THz setups are ill suited for integration with microscale quantum materials and offer fewer opportunities for spectral engineering. Integrated photonics promise compact, high-bandwidth, engineerable THz devices for spectroscopy and sensing. Recent developments in the field have shown high THz conversion efficiency on an integrated platform, with phase matching through tailored waveguide design, leveraging the high nonlinearity of lithium niobate while minimizing losses. We present thin-film lithium niobate devices with integrated bow-tie antennas and for on-chip terahertz generation and detection. Fabricated devices show robust optical coupling, and ongoing measurements aim to resolve the terahertz emission through electro-optic sampling. These devices are compatible with cryogenic integration and provide enhanced THz field overlap with target materials, enabling more precise electro-optic sampling of quantum systems.