不同偏振态飞秒激光在PMMA上的成丝现象

Filamentation Phenomenon of Different Polarized Femtosecond Laser in PMMA

随着飞秒激光技术的不断成熟和聚甲基丙烯酸甲酯(PMMA)的大量应用,对PMMA光学性能的研究逐渐成为研究热点。飞秒激光在透明材料加工过程中会出现成丝现象,分析了自聚焦和丝状物的产生原理。偏振态是激光光束的重要特征之一,利用空间光调制器、1/2波片和1/4波片组合可实现对线偏振光、圆偏振光、径向偏振光和角向偏振光的控制。利用产生的1μJ偏振光在PMMA上刻线,对比分析不同偏振光的成丝长短和成丝起始位置。实验结果表明:线偏振光和圆偏振光的成丝长度较短,其中线偏振光的成丝位置距离入射面最近;径向偏振光和角向偏振光的成丝长度较长,且成丝位置距离入射面最远。

With the development of femtosecond laser technology and wide applications of polymethyl methacrylate （PMMA）, the research on optical properties of PMMA has become a hot spot. Filamentation phenomenon appears in the process of transparent materials by femtosecond laser. Generation principles of self-focusing and filamentous are analyzed. One of the most important characteristics of laser beam is polarization state. Linearly polarized light, circularly polarized light, radially polarized light and angularly polarized light can be controlled by the combination of spatial light modulator, 1/2 wave plate and 1/4 wave plate. Generated polarized light with energy of 1 /μJ is used in the line processing on PMMA, and then the comparative analysis is conduct on the length and initial position of filamentation under different polarized light. Experimental results show that linearly polarized light and circularly polarized light result in filamentation with short length, and filamentation position of linearly polarized light is close to the incident plane. Radially polarized light and azimuthally polarized light result in long length, and the distance of filamentation position to the incident plane is long.