For several decades, optical near-field microscopy has facilitated pioneering investigations of photonic excitations at the nanoscale. In recent years, near-field microscopy of terahertz fields has emerged as an important tool for experiments involving phononic and electronic phenomena, rich spatiotemporal dynamics and highly nonlinear processes. Building on this foundation, this Perspective elucidates the transformative opportunities provided by terahertz near-field microscopy to probe ultrafast phase transitions, helping to tackle previously inaccessible challenges of condensed matter physics. Laser-driven phase transitions in many systems are accompanied by the generation of terahertz pulses with spatiotemporal features governed by the complex physics underlying the phase transition. The characterization of these emitted pulses using terahertz near-field microscopy techniques could therefore support the investigation of ultrafast phase transition dynamics. This approach could, for example, allow the observation of ultrafast topological transitions in quantum materials, showcasing its ability to clarify the dynamic processes underlying phase changes.

几十年来，光学近场显微镜促进了纳米尺度光子激发的开创性研究。近年来，太赫兹场的近场显微镜已成为涉及声子和电子现象、丰富的时空动力学和高度非线性过程的实验的重要工具。在此基础上，本视角阐明了太赫兹近场显微镜为探测超快相变提供的变革机会，有助于解决凝聚态物理以前难以应对的挑战。许多系统中激光驱动的相变都伴随着太赫兹脉冲的生成，其时空特征受相变背后的复杂物理控制。因此，使用太赫兹近场显微镜技术对这些发射脉冲进行表征可以支持超快相变动力学的研究。例如，这种方法可以观察量子材料中的超快拓扑转变，展示其阐明相变背后的动态过程的能力。