Flexible temporal cloak with retrievable events

The pursuit of invisibility cloaks has long been a central theme in science fiction literature. One approach involves altering the waveform transmitted to the observer in the spatial domain, represented by meta-materials. Another approach is to open a window in the time domain. Specifically, researchers for the first time opened a single or periodic time gap in the probe light sent to the observer, thereby hiding an event within this time gap [Nature481, 62 (2012)10.1038/nature10695]. However, the absence of an optical carrier in the opened window prevented the recovery of the hidden event even for the cooperator. Now, we have demonstrated a novel temporal cloak that can recover hidden events. In this temporal cloak, the opening and closing of time gaps are achieved through the precise manipulation of photon density and phase synchronization in the injection-locked laser. During the process, the inevitable spontaneous emission photons are utilized to carry the event information. The cloaking window demonstrates both flexibility and reconfigurability, with its size achieving a breakthrough extension to 2.5 µs compared with dispersion-based methods. These advancements represent a significant step towards the realization of time cloaking and have a direct impact on secure communication.