Patent ID: 6482199
Filing Date: 2002-11-19
Classification: A61B,A61C,A61F,B23K,G01N

Abstract:
A method for a controlled, variable rate material modification by a pulsed electromagnetic radiation beam, the interaction between the pulsed electromagnetic radiation beam and the material providing a modification threshold volumetric power density, the method comprising:a) providing a source capable of generating an output beam comprised of a sequence of electromagnetic pulses, each electronic pulse having a pulse duration in the range of approximately 1 femtosecond to approximately 100 millisecond; b) operating the pulse source and manipulating the beam parameters so that the deposited volumetric power density within the targeted volume is greater than the threshold power density for material modification, so that control of power density is achieved by varying either one or more of the following parameters: the beam spot size at the targeted location, the duration of the electromagnetic pulsed emissions, the energy of the electromagnetic pulsed emissions, the wavelength of the electromagnetic pulsed emissions, or by spatially and temporally varying the absorption and/or scattering characteristics of the material at the targeted region; c) allowing interaction energy transients caused by the electromagnetic radiation pulse to substantially decay so that material modification is effected, the material modification include one or more of the following alterations: chemical changes, physical changes, changes to viscoelastic properties, changes to optical properties, thermal properties, chemical and physical breakdown, disintegration, ablation melting and vaporization; d) operating the pulse source at a pulse repetition rate greater than 0.1 pulses per second until a desired volume of the material has been modified.