The development of ultra-intense and ultra-short light sources is currently a subject of intense research driven by the discovery of novel phenomena in the realm of relativistic optics, such as the production of ultrafast energetic particle and radiation beams for applications. It has been a long-standing challenge to unite two hitherto distinct classes of light sources: those achieving relativistic intensity and those with pulse durations approaching a single light cycle. While the former class traditionally involves large-scale amplification chains, the latter class places high demand on the spatiotemporal control of the electromagnetic laser field. Here, we present a light source producing waveform-controlled 1.5-cycle pulses with a 719 nm central wavelength that can be focused to relativistic intensity at a 1 kHz repetition rate based on nonlinear post-compression in a long hollow-core fiber. The unique capabilities of this source allow us to observe the first experimental indications of light waveform effects in laser wakefield acceleration of relativistic energy electrons.

超强和超短光源的开发目前是一个相对的研究热点，这是由于相对论光学领域中发现了新现象，例如生产超快高能粒子和辐射束等。迄今为止，将两类截然不同的光源组合在一起一直是一项长期的挑战：达到相对论强度的光源和具有接近单个光周期的脉冲持续时间的光源。尽管前一类传统上涉及大规模放大链，但后一类对电磁激光场的时空控制提出了很高的要求。在这里，我们介绍一种产生波形控制的光源1。中心波长为719 nm的5周期脉冲，可以基于长空心光纤中的非线性后压缩，以1 kHz重复频率聚焦到相对论强度。该光源的独特功能使我们能够观察到相对论能量电子在激光尾波加速中的光波形效应的第一个实验指示。