Theory analysis of wavelength dependence of laser-induced phase explosion of silicon
- Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
Wavelength dependence of laser ablation of silicon was investigated with nanosecond ultraviolet, visible, and infrared laser pulses in the irradiance range from 3x10{sup 10} to 1x10{sup 12} W/cm{sup 2}. For 266 and 532 nm laser pulses, the depth of laser-produced crater shows a dramatic increase at a laser irradiance threshold of approximately 2x10{sup 10} and 4x10{sup 11} W/cm{sup 2} respectively, above which, large micron-sized particulates were observed to eject from the target about 300-400 ns after the laser pulse. In contrast, for 1064 nm pulse, this dramatic increase was not observed. The underlying mechanism for the observed threshold phenomenon is presented in this study, which can be attributed to the thermal diffusion and subsequent explosive boiling after the completion of the interaction between the nanosecond laser pulse and silicon. Based on our delayed phase explosive model, the ablation depths were calculated for different wavelengths and compared to experimental results. Plasma shielding during laser irradiation was included in the model, which plays a key role to the coupling of laser energy to the irradiated material.
- OSTI ID:
- 21185862
- Journal Information:
- Journal of Applied Physics, Vol. 104, Issue 8; Other Information: DOI: 10.1063/1.2978369; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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