The ablation processes of Cu film are investigated using temporal shaped femtosecond pulse trains. The depth is modulated by changing the number and interval of the sub-pulses. The underlying ultrafast dynamic processes are discussed based on plasma shielding and electron multiple heating mechanisms. When the sub-pulse interval is less than 0.4 ps electron multiple heating is the dominant mechanism, while the plasma shielding dominates the subsequent ablation processes when the sub-pulse interval is larger than 0.4 ps. The curve of depth obtained by three pulse trains shows more significant oscillation as the function of sub-pulse interval under the low-fluence. We propose that the oscillation of depth is due to the coherent phonon oscillation excited by the pulse train. The study provides a basis for giving insight into the ultrafast dynamics for improving micromachining and nano-fabrications using shaped femtosecond pulse trains.

使用时间形状的飞秒脉冲序列研究了Cu膜的烧蚀过程。通过改变子脉冲的数量和间隔来调制深度。基于等离子体屏蔽和电子多重加热机制，讨论了潜在的超快动态过程。当子脉冲间隔小于0.4 ps时，电子多重加热是主要机制，而当子脉冲间隔大于0.4 ps时，等离子屏蔽在随后的烧蚀过程中占主导地位。在低通量下，由三个脉冲序列获得的深度曲线显示出更显着的振荡，这是子脉冲间隔的函数。我们提出深度的振荡是由于脉冲序列激发的相干声子振荡。