We describe laser ablation of Si under water by 5 ns, 355 nm and 100 fs, 800 nm pulses. Compared to that in air, an approximately twofold improvement in the ablation rate is found in water for femtosecond and nanosecond pulses. For higher laser irradiances, the plasma that forms at the water-air interface hampers further improvement of the ablation rate. We investigated the enhanced ablation process in water and found that the cavity-confinement geometry that increases the laser energy coupling to the target and allows more energy to be transferred to the cavity sidewalls plays an important role in the escalated material removal process. In addition, we show that the water layer that effectively reduces the oxidation and redeposition of the ablated debris is also responsible for improvements in the ablation process.
© 2005 Optical Society of America
(320.2250) Ultrafast optics : Femtosecond phenomena
(320.4240) Ultrafast optics : Nanosecond phenomena
(320.7130) Ultrafast optics : Ultrafast processes in condensed matter, including semiconductors
Jun Ren, Michael Kelly, and Lambertus Hesselink, "Laser ablation of silicon in water with nanosecond and femtosecond pulses," Opt. Lett. 30, 1740-1742 (2005)