Emission and absorption of light lie at the heart of light–matter interaction¹. Although emission and absorption rates are regarded as intrinsic properties of atoms and molecules, various ways to modify these rates have been sought in applications such as quantum information processing², metrology³ and light-energy harvesting⁴. One promising approach is to utilize collective behaviour of emitters in the same way as in superradiance⁵. Although superradiance has been observed in diverse systems^3,6,7,8,9,10, its conceptual counterpart in absorption has never been realized¹¹ until now. Here we demonstrate enhanced cooperative absorption—superabsorption—by implementing a time-reversal process of superradiance. The observed superabsorption rate is much higher than that of ordinary absorption, with the number of absorbed photons scaling with the square of the number of atoms, exhibiting the cooperative nature of superabsorption. The present superabsorption—which performs beyond the limitations of conventional absorption—can facilitate weak-signal sensing¹, light-energy harvesting¹¹ and light–matter quantum interfaces².

光的发射和吸收是光与物质相互作用的核心¹。^{尽管发射和吸收速率被认为是原子和分子的固有特性，但在量子信息处理2}、计量学³和光能收集⁴等应用中，人们一直在寻找各种方法来修改这些速率。^{一种有前途的方法是以与超辐射5}相同的方式利用发射器的集体行为。尽管已经在不同的系统中观察到超辐射 3、6、7、8、9、10 ^，但它在吸收方面的概念对应物从未实现¹¹到目前为止。在这里，我们通过实施超辐射的时间反转过程证明了增强的协同吸收 - 超吸收。观察到的超吸收率远高于普通吸收，吸收的光子数与原子数的平方成正比，表现出超吸收的协同性质。目前的超吸收——其性能超出了传统吸收的限制——可以促进弱信号传感¹、光能收集¹¹和光物质量子界面²。