We give a protocol for ghost imaging in a way that is always counterfactual—while imaging an object, no light interacts with that object. This extends the idea of counterfactuality beyond communication, showing how this interesting phenomenon can be leveraged for metrology. Given, in the infinite limit, no photons ever go to the imaged object, it presents a method of imaging even the most light-sensitive of objects without damaging them. Even when not in the infinite limit, it still provides a many-fold improvement in visibility and signal-to-noise ratio over previous protocols, with over an order of magnitude reduction in absorbed intensity.

中文翻译：

---

反事实鬼成像

我们以一种总是反事实的方式给出了鬼成像协议——在对物体成像时，没有光与该物体相互作用。这将反事实的想法扩展到了交流之外，展示了如何将这种有趣的现象用于计量学。鉴于在无限极限下，没有光子到达成像物体，它提供了一种即使是对光最敏感的物体也能成像而不损坏它们的方法。即使不在无限极限内，它仍然比以前的协议在可见性和信噪比方面提供了许多倍的改进，吸收强度降低了一个数量级。