Patent ID: 8524139
Filing Date: 2013-09-03
Classification: B23K,B29C,B41M

Abstract:
1. A method of removing material from a sample by laser ablation while reducing redeposition, the method comprising: providing an apparatus for laser micromachining having an airtight evacuable chamber for holding a sample, a source of a precursor gas, and a laser system for operating on the sample in the vacuum chamber, the laser system generating a pulsed laser beam having an energy great enough to ablate the sample; loading a sample into the vacuum chamber; filling the vacuum chamber with a desired concentration of precursor gas to form an atmosphere of precursor gas particles in the vacuum chamber around the sample, the precursor gas being a gas that will react with the sample material, when sufficient energy is provided to initiate said reaction, to form a volatile compound that will not redeposit onto the sample surface; and directing the laser at the sample to ablate the surface, the laser operated at a fluence greater than the ablation threshold of the sample material so that sample particles are ejected into the precursor gas atmosphere in the vacuum chamber; the laser providing sufficient energy to the ejected sample particles to initiate the reaction with the precursor gas particles; wherein directing the laser at the sample comprises directing the laser at the sample using a photonic fiber having negative group-velocity dispersion: wherein the desired concentration of precursor gas is high enough that that the volume of ejected particles that collide with and react with gas particles and are thereby volatilized is high enough to significantly reduce redeposition onto the sample.