title: In situ 24 kHz coherent imaging of morphology change in laser percussion drilling.
abstract: We observe sample morphology changes in real time (24 kHz) during and between percussion drilling pulses by integrating a low-coherence microscope into a laser micromachining platform. Nonuniform cut speed and sidewall evolution in stainless steel are observed to strongly depend on assist gas. Interpulse morphology relaxation such as hole refill is directly imaged, showing dramatic differences in the material removal process dependent on pulse duration/peak power (micros/0.1 kW, ps/20 MW) and material (steel, lead zirconate titanate PZT). Blind hole depth precision is improved by over 1 order of magnitude using in situ feedback from the imaging system.
authors.affiliation: Department of Physics, Engineering Physics and Astronomy, Queen's University, Kingston, Canada K7L 3N6. webster@physics.queensu.ca
authors.forename: Paul J L
authors.initials: PJ
authors.lastname: Webster
authors.forename: Joe X Z
authors.initials: JX
authors.lastname: Yu
authors.forename: Ben Y C
authors.initials: BY
authors.lastname: Leung
authors.forename: Mitchell D
authors.initials: MD
authors.lastname: Anderson
authors.forename: Victor X D
authors.initials: VX
authors.lastname: Yang
authors.forename: James M
authors.initials: JM
authors.lastname: Fraser
mesh_terms: D007834:Lasers; D008422:Materials Testing / Q000379:methods*; D008853:Microscopy / Q000379:methods*; D013193:Stainless Steel / Q000737:chemistry* / Q000528:radiation effects*; D013499:Surface Properties; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D013193:Stainless Steel