Near-Field Laser Heating for Surface Nano-Sampling and Processing Multi-Parametric Modeling and Experimental Studies
Résumé
To satisfy the growing demands of modern science and industry, laser ablation methods are under continuous development. The development of laser ablation methods has significantly expanded the scope of their applications for modern laser-assisted micro and nanotechnologies. In particular, in our studies on near-field laser ablation, the possibility to perform laser ablation and surface processing with a nanometric resolution was demonstrated with laser field enhancement near a tip of an atomic-force microscope. Laser ablation, in our case, may be regarded as a result of the local near-field heating of a sample surface. Laser ablation efficiency and accuracy are affected by both the sample properties (thermal diffusivity, absorption coefficient, etc.) and the near-field parameters (spatial distribution, wavelength, laser pulse duration, tips nature and dimension, etc.). The modeling of the temperature distribution resulting from the near-field heating of the sample surface may be seen as an appropriate procedure to analyze these complex multi parametric effects and corresponding interrelations. The paper presents the results on the modeling for the near-field heating of metal or semiconductor surfaces (gold, tantalum and silicon wafer) along with those obtained experimentally with nanosecond laser pulses (4 ns, 266 nm, 10 Hz, linear p-polarization) and an atomic-force microscope in air, under normal conditions. The properties of nanometer scale craters are in good correlation with the model predictions. The possible improvements of the near-field ablation with a femtosecond laser will be discussed.