All light has structure, but only recently has it been possible to control it in all its degrees of freedom and dimensions, fuelling fundamental advances and applications alike. Here we review the recent advances in ‘pushing the limits’ with structured light, from traditional two-dimensional transverse fields towards four-dimensional spatiotemporal structured light and multidimensional quantum states, beyond orbital angular momentum towards control of all degrees of freedom, and beyond a linear toolkit to include nonlinear interactions, particularly for high-harmonic structured light. Using a simple interference argument, centuries old, we weave a story that highlights the common nature of seemingly diverse structures, presenting a modern viewpoint on the classes of structured light, and outline the possible future trends and open challenges.

所有的光都有结构，但直到最近才有可能在所有自由度和尺寸上对其进行控制，从而推动了基础技术的进步和应用。在这里，我们回顾了结构光“突破极限”的最新进展，从传统的二维横向场到时空结构光和多维量子态，从空间角动量到控制所有自由度，再到超越空间角动量。线性工具包，其中包括非线性相互作用，特别是对于高谐波结构光。我们使用一个简单的干涉论证（已有数百年历史），编织了一个故事，强调了看似多样的结构的共同本质，提出了关于结构光类别的现代观点，并概述了未来可能的趋势和开放的挑战。