Generation and detection of terahertz pulses in thin-film lithium niobate photonic circuits (Invited Paper)

We present thin-film lithium niobate integrated photonic circuits specifically engineered for the on-chip generation and detection of broadband terahertz pulses. By exploiting the exceptionally large second-order nonlinear response of lithium niobate at millimeter-wave and terahertz frequencies, together with its low optical propagation losses, we demonstrate hybrid integrated architectures that seamlessly combine planar antennas and transmission lines for terahertz radiation with optical waveguides for efficient optical beam delivery and manipulation. The tight co-design of metallic terahertz structures and guided optical modes enables phase-matching conditions that are fundamentally inaccessible in bulk lithium niobate, thereby enhancing optical–terahertz interaction efficiency. Beyond spectroscopy and ultrafast signal processing, this integrated platform provides a promising technological launchpad for future photonic terahertz transceivers targeting emerging short-range THz communication and 6G systems