More than a century ago, Albert Einstein presented his general theory of gravitation (GR) to the Prussian Academy of Sciences. One of the predictions of the theory is that not only particles and objects with mass, but also the quanta of light, photons, are tied to the curvature of space-time, and thus to gravity. There must be a critical compactness, above which photons cannot escape. These are black holes (henceforth BH). It took 50 years after the theory was announced before possible candidate objects were identified by observational astronomy. And another 50 years have passed, until we finally have in hand detailed and credible experimental evidence that BHs of 10 to \(10^{10}\) times the mass of the Sun exist in the Universe. Three very different experimental techniques, but all based on Michelson interferometry or Fourier-inversion spatial interferometry have enabled the critical experimental breakthroughs. It has now become possible to investigate the space-time structure in the vicinity of the event horizons of BHs. We briefly summarize these interferometric techniques, and discuss the spectacular recent improvements achieved with all three techniques. Finally, we sketch where the path of exploration and inquiry may go on in the next decades.

一个多世纪前，阿尔伯特·爱因斯坦向普鲁士科学院提出了他的广义引力理论（GR）。该理论的预测之一是，不仅粒子和有质量的物体，而且光的量子（光子）都与时空曲率有关，从而与引力有关。必须有一个临界紧致度，超过这个紧致度光子就无法逃逸。这些就是黑洞（以下简称 BH）。该理论公布后过了 50 年，观测天文学才确定了可能的候选天体。又过了 50 年，我们终于掌握了详细且可靠的实验证据，证明宇宙中存在质量为太阳质量10 到\(10^{10}\)倍的 BH。三种截然不同的实验技术，但都基于迈克尔逊干涉测量法或傅里叶反演空间干涉测量法，实现了关键的实验突破。现在研究黑洞事件视界附近的时空结构已经成为可能。我们简要总结了这些干涉测量技术，并讨论了这三种技术最近取得的惊人改进。最后，我们概述了未来几十年探索和探究的道路可能会走向何方。