500 GHz field-resolved detection in thin-film lithium niobate devices

In this work, we show the coherent reconstruction of terahertz (THz) transients in thin-film lithium niobate integrated photonics circuits. Our devices modulate the intensity of a probe beam guided through a Mach-Zehnder interferometer (MZI) structure, under the illumination of an impinging THz wave. Golden bow-tie antennas fabricated along the waveguides, collect and tightly squeeze the THz radiation across their gap, greatly enhancing the THz-probe nonlinear interaction. We show that the probe intensity modulation reproduces the oscillations of the THz electric field established across the gaps of the metallic antennas.