A Compact High-Repetition-Rate Intense THz Source for Atomic-Scale Materials Characterization

Abstract

High-intensity terahertz (THz) sources combining high repetition rates, strong field amplitudes, and long-term stability are key enabling technologies for next-generation ultrafast photonics. However, simultaneously achieving these characteristics in a compact and practical architecture remains a major challenge. Here, we report a high-performance tabletop THz source delivering intense single-cycle pulses at 100 kHz, generated by optical rectification in lithium niobate using an optimized echelon-based tilted-pulse-front scheme and driven by an industrial-grade ytterbium laser. The source achieves optical-to-THz conversion efficiencies exceeding 0.13% at room temperature, peak electric fields of several hundred kV/cm, and excellent long-term stability, establishing a robust platform for high-average-power strong-field THz applications. As a proof of concept, the source was integrated into an atom probe tomography (APT) instrument. APT reconstructs the three-dimensional chemical composition of materials through field-induced ion emission from a sharp nanotip. While THz-assisted ion emission has been shown to improve analytical performance by reducing thermal effects, previous demonstrations were limited to low-repetition-rate THz sources, restricting throughput and accessible analysis volumes. Using an aluminum nanotip, we demonstrate efficient THz-assisted APT at 100 kHz and benchmark its performance against conventional voltage- and laser-assisted operation. The high repetition rate enables rapid large-volume acquisition while improving mass resolving power, reducing thermal tailing, and preserving high-quality three-dimensional reconstructions. Beyond APT, this work establishes a compact and scalable high-repetition-rate THz platform for strong-field physics, nonlinear THz photonics, ultrafast spectroscopy, and material characterization at the nanoscale.