Time dependent evolution of refractive index around a molten pool in glass welding by ultra-short pulses

The time-dependent phase evolution is shown for different feed speeds. The units of the phase legend is Pi. The time duration between the shown frames is 44.4 µs. The laser pulse repetition rate is 450 kHz, the (original) camera frame rate is 225 kHz. The image scale is 2.13 µm/pxl. For more details on original experiments see: Alexeev I, Heberle J, Cvecek K, Nagulin, Schmidt. High Speed Pump-Probe Apparatus for Observation of Transitional Effects in Ultrafast Laser Micromachining Processes. Micromachines 2015;6:1914-22.不同进给速度下的时变相演化过程如图所示。 相位图例的单位为Pi（π）。 所示帧之间的时间间隔为44.4 µs。激光脉冲重复频率为450 kHz，原始相机帧率为225 kHz。 图像比例尺为2.13 µm/pxl。 如需了解原始实验的更多细节，请参阅： Alexeev I, Heberle J, Cvecek K, Nagulin, Schmidt. 用于超快激光微细加工过程过渡效应观测的高速泵浦-探测装置, Micromachines, 2015;6:1914-1922.