The invention consists of a method for high precision machining (cutting,
drilling, sculpting) of metals and alloys. By using pulses of a duration
in the range of 10 femtoseconds to 100 picoseconds, extremely precise
machining can be achieved with essentially no heat or shock affected zone.
Because the pulses are so short, there is negligible thermal conduction
beyond the region removed resulting in negligible thermal stress or shock
to the material beyond approximately 0.1-1 micron (dependent upon the
particular material) from the laser machined surface. Due to the short
duration, the high intensity (>10.sup.12 W/cm.sup.2) associated with
the interaction converts the material directly from the solid-state into
an ionized plasma. Hydrodynamic expansion of the plasma eliminates the
need for any ancillary techniques to remove material and produces
extremely high quality machined surfaces with negligible redeposition
either within the kerf or on the surface. Since there is negligible
heating beyond the depth of material removed, the composition of the
remaining material is unaffected by the laser machining process. This
enables high precision machining of alloys and even pure metals with no
change in grain structure.