Etching a substrate: processes – Gas phase etching of substrate – Application of energy to the gaseous etchant or to the...
Patent
1996-01-11
1998-02-24
Powell, William
Etching a substrate: processes
Gas phase etching of substrate
Application of energy to the gaseous etchant or to the...
156345, 216 67, 606 11, 607 89, B44C 122
Patent
active
057208948
ABSTRACT:
A method and apparatus is disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment.
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Da Silva Luiz B.
Feit Michael D.
Glinsky Michael E.
Matthews Dennis L.
Neev Joseph
Powell William
The Regents of the University of California
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