Sheinman Matthew, Erramilli Shyamsunder, Ziegler Lawrence, Hong Mi K, Mertz Jerome
Opt Lett. 2022 Feb 1;47(3):577-580. doi: 10.1364/OL.448106.
We present a method for acquiring a sequence of time-resolved images in a single shot, called single-shot non-synchronous array photography (SNAP). In SNAP, a pulsed laser beam is split by a diffractive optical element into an array of angled beamlets whose illumination fronts remain perpendicular to the optical axis. Different time delays are imparted to each beamlet by an echelon, enabling them to probe ultrafast dynamics in rapid succession. The beamlets are imaged onto different regions of a camera by a lenslet array. Because the illumination fronts remain flat (head-on) independently of beamlet angle, the exposure time in SNAP is fundamentally limited only by the laser pulse duration, akin to a "global shutter" in conventional imaging. We demonstrate SNAP by capturing the evolution of a laser induced plasma filament over 20 frames at an average rate of 4.2 trillion frames per second (Tfps) and a peak rate of 5.7 Tfps.
我们提出了一种在单次拍摄中获取时间分辨图像序列的方法，称为单次非同步阵列摄影（SNAP）。在SNAP中，脉冲激光束由衍射光学元件分裂成一系列成角度的子光束，其照明前沿保持垂直于光轴。阶梯光栅为每个子光束赋予不同的时间延迟，使其能够快速连续地探测超快动力学。子光束通过微透镜阵列成像到相机的不同区域。由于照明前沿独立于子光束角度保持平坦（正面），SNAP中的曝光时间从根本上仅受激光脉冲持续时间的限制，类似于传统成像中的“全局快门”。我们通过以平均每秒4.2万亿帧（Tfps）和峰值速率5.7 Tfps捕获激光诱导等离子体细丝在20帧上的演化来演示SNAP。
