| 摘要 |
A method and apparatus for laser cutting a target material is disclosed. The method includes the steps of generating laser pulses from a laser system and applying the laser pulses to the target material so that the laser pulses cut through the material. The laser pulses have an approximately ellipse shaped spot, have a temporal pulse width shorter than about 100 nanoseconds, and have an energy density from about 2 to about 20 times the ablation threshold energy of the target material. The laser pulses are applied to the material such that the major axis of the ellipse shaped spot moves parallel to the cutting direction. The spot has a leading edge and a trailing edge on the major axis, and the energy density of each laser pulse increases from zero to a maximum along the leading edge and decreases back to zero along the trailing edge. The apparatus is a laser system for cutting a target material that includes: a seed laser system for producing a first pulse laser beam; a laser amplifier for amplifying the first pulse laser beam to produce an amplified pulse laser beam; a harmonic generation system for converting the amplified pulse laser beam into a second pulse laser beam having a shorter wavelength; a focussing system for focussing the second pulse laser beam to an approximately ellipse shaped third pulse laser beam; and a motion control system for moving a target material contacted by the third pulse laser beam. |
