记录飞秒级超快动态过程的脉冲数字全息技术

采用脉冲数字全息技术实现对飞秒级超快动态过程的数字显微全息记录.其中，全息记录系统将单脉冲分割成具有飞秒至皮秒量级时间延迟的角度相同的物光子脉冲序列和具有同样时间延迟的角度不同的参考光子脉冲序列，并以空间角分复用的方式在普通CCD的一帧图像上记录下包含多张子全息图的复合全息图，然后通过数字傅里叶变换和数字滤波的方法，分别再现出每张子全息图所记录的图像.通过对飞秒激光激发空气电离过程的全息记录，获得了具有飞秒时间分辨的等离子体形成和传播过程的动态图像. 关键词： 超短脉冲激光 飞秒全息 脉冲数字全息 空间角分复用

Pulsed digital holographic recording of ultra-fast process of the femto-second order

In this paper, we report a pulsed digital micro-holography system for recording ultra-fast process of the order of femto-second. Two sub-pulse-train generators can be adjusted independently for generating reference beams with different spatial angles and object beams of the same angle, respectively, and the time delay between the sub-pulses can be adjusted from pico-senconds to femto-seconds. In the experiment, the ultra-fast dynamic process of air ionization induced by a femto-second laser pulse is recorded by the holographic recording system through spatially angular multiplexing, and both of the digitally reconstructed images in intensity and phase are obtained, which show the dynamic process of formation and propagation of the plasma with a time resolution of the order of femto-second.