Method and apparatus for high precision variable rate material, removal and modification
OwnerJoseph Neevinventor
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Abstract
A method and apparatus is disclosed for fast precise material processing and modification which minimizes collateral damage. Utilizing optimized, pulsed electromagnetic energy parameters leads to an interaction regime which minimizes residual energy deposition. Advantageously, removal of cumulative pulse train residual energy is further maximized through the rapid progression of the ablation front which move faster than the thermal energy diffusion front, thus ensuring substantial removal of residual energy to further minimize collateral thermal damage.
Claims16
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.
A method for a high precision, highly controllable, variable rate, material removal by a continuously emitting, continuous wave (CW) beam of electromagnetic radiation, the interaction between the electromagnetic radiation, and the material being such that a material removal depth within is approximately equal to an energy deposition depth within the target material, the method comprising the steps of:
- a) providing a source capable of generating an output beam comprised of continuously emitted electromagnetic radiation;
- b) redistributing the beam in time and space to form at least one modified beam comprising a plurality of pulses;
- c) directing said modified beam(s) so that their energy distribution at any given location on the target material forms a sequence of electromagnetic pulses, each electromagnetic pulse having a pulse duration between approximately 1 femtosecond and approximately 10 millisecond;
- d) operating said source and manipulating parameters of the beam so that the electromagnetic pulse's power densities within the region targeted for modification are between approximately 104 W/cm3 approximately 1018 W/cm3 and are larger than a power density threshold for material ablation;
- e) allowing the electromagnetic energy absorbed by the material to complete the material ablation, so that substantially most of the deposited electromagnetic energy is removed from the target material with an ejected portion of the material;
- f) repeating said electromagnetic energy absorption, ablation, and energy removal steps at a pulse repetition rage greater than 0.1 pulses per second so that substantially most of the cumulative residual thermal energy left in the material by a pulse train is removed by the commutative ablation, and at a pulse repetition rate less than approximately 100,000 pulses per second until a sufficient depth of material has been removed while mitigating transfer of thermal or mechanical energy into the remaining material and thus mitigating collateral damage thereto.
Dependencies are inferred from the claim text.