Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 61005, Republic of Korea.
Sci Rep. 2017 Mar 7;7:43302. doi: 10.1038/srep43302.
Recording processes and events that occur on sub-nanosecond timescales poses a difficult challenge. Conventional ultrafast imaging techniques often rely on long data collection times, which can be due to limited device sensitivity and/or the requirement of scanning the detection system to form an image. In this work, we use a single-photon avalanche detector array camera with pico-second timing accuracy to detect photons scattered by the cladding in optical fibers. We use this method to film supercontinuum generation and track a GHz pulse train in optical fibers. We also show how the limited spatial resolution of the array can be improved with computational imaging. The single-photon sensitivity of the camera and the absence of scanning the detection system results in short total acquisition times, as low as a few seconds depending on light levels. Our results allow us to calculate the group index of different wavelength bands within the supercontinuum generation process. This technology can be applied to a range of applications, e.g., the characterization of ultrafast processes, time-resolved fluorescence imaging, three-dimensional depth imaging, and tracking hidden objects around a corner.
记录发生在纳秒以下时间尺度的过程和事件是一个具有挑战性的难题。传统的超快成像技术通常依赖于较长的数据采集时间，这可能是由于设备灵敏度有限和/或需要扫描检测系统以形成图像。在这项工作中，我们使用具有皮秒定时精度的单光子雪崩二极管阵列相机来检测光纤包层散射的光子。我们使用这种方法拍摄超连续谱产生过程并跟踪光纤中的 GHz 脉冲串。我们还展示了如何使用计算成像来提高阵列的有限空间分辨率。相机的单光子灵敏度和不扫描检测系统导致总采集时间很短，根据光强度，最短可低至几秒钟。我们的结果允许我们计算超连续谱产生过程中不同波长带的群折射率。这项技术可应用于一系列应用，例如超快过程的特性描述、时间分辨荧光成像、三维深度成像和跟踪拐角处的隐藏物体。
