高厚度薄膜-泡沫平面调制靶的飞秒激光微加工

 利用数值孔径为0.14的显微物镜聚焦中心波长800 nm、脉宽120 fs、重复频率1 kHz的飞秒激光，采用焦点逐线扫描等距下移方式，选取的入射平均功率为30 mW，加工速度为300 μm/s，对瑞利-泰勒(R-T)不稳定性实验靶用的厚度1.5 mm聚苯乙烯（PS）薄膜-聚4-甲基-1-戊烯（PMP）泡沫双层复合长条块体样品进行精确切割成型，并与纳秒激光切割情形对比。结果表明：利用飞秒激光微加工有效控制了切割区变形和材料分层，获得了整齐的切割边缘和平坦的切割面，样品最大切割深度超过800 μm。

Thick modulated planar film-foam target fabricated by femtosecond laser micromachining

Dual layer Polystyrene(PS)-poly-4-methyl-1-pentene(PMP) foam with thickness of 1.5 mm, used in Rayleigh-Taylor hydrodynamic instability experiments, was accurately cut employing femtosecond laser irradiation with 800 nm central wavelength, 120 fs duration, 1 kHz repetition rate focused by microscopic objective(5×, NA=0.14). During the cutting, the manner of uniform step descending of laser focus and processing parameters with average incident power of 30 mW, cutting speed of 300 μm/s were adopted. Compared with the case of nanosecond laser cutting, detrimental distortion and delamination of the dual heterogeneous layer around the femtosecond laser irradiated zone were effectively avoided. Uniform cutting edge and smooth facet were also obtained, with maximal cutting thickness exceeding