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采用1kHz,800nm,50fs—24ps的钛宝石激光脉冲对单晶硅样品在空气和水溶液环境中的烧蚀加工特性进行了研究.实验观察到了超短脉冲激光在空气氛围中烧蚀形成的双层环状结构,分析揭示了加工区域中心和边缘的烧蚀物理机制分别为热熔化和库仑爆炸,并测量了双层环状结构半径随入射激光能量、脉冲数及持续时间等的变化关系,结果表明获取较大深-宽比的加工效果需选择小能量脉冲激光的多次作用.在水溶液环境中,实验发现飞秒激光在样品表面诱导产生了亚微米量级的多孔状结构,而皮秒激光则更容易实现对硅表面的非热性去除.这是由于激光诱导的光机械应力和空泡效应随脉冲宽度变大而增强所致,在实验上确立了区分这两种不同加工状态的临界脉冲宽度.
The ablation processing characteristics of single crystal silicon samples in air and aqueous solution were investigated by using 1 kHz, 800nm and 50fs-24ps sapphire laser pulses.The birefringence of ultrashort pulsed laser ablated in the air was observed The results show that the physical mechanisms of ablation at the center and edge of the processing area are respectively hot-melt and Coulomb explosion. The relationship between the radius of the double-ring structure and the incident laser energy, pulse number and duration is also measured. The results show that the femtosecond laser induces the submicron-order porous structure on the sample surface in an aqueous solution environment, while the picosecond Laser is more likely to achieve non-thermal removal of the silicon surface.This is due to laser-induced optical mechanical stress and the void effect increases with the pulse width increases due to the experiment established to distinguish between the two different processing conditions Critical pulse width.