%0 Journal Article
%K Model
%K Particle
%K Particles
%K Lead
%K Transformation
%K USA
%K Surface
%K Power
%K Films
%K Ablation
%K Laser
%K Laser ablation
%K Laser ablation
%K Time-resolved
%K State
%K Time
%K Ca
%K E
%K Liquid
%K Sample
%K C
%K Crater
%K Volume
%K Nanosecond
%K Metal
%K Nanosecond laser
%K Depth
%K Silicon
%K Layer
%K Threshold
%K Generation
%K Particulates
%K Irradiance
%K Circulation
%K Phase explosion
%K Phase-explosion
%K Physics
%K Single-crystal
%K Dielectric
%K Thickness
%K Transparency
%K Critical state
%K Critical-state
%K Deep
%K Ejection
%A Jong-Hyun Yoo
%A Sungho Jeong
%A Xianglei Mao
%A Ralph Greif
%A Richard E Russo
%B Applied Physics Letters
%D 2000
%F Laser
%G eng
%N 6
%P 783-785
%R 10.1063/1.125894
%T Evidence for phase-explosion and generation of large particles during high power nanosecond laser ablation of silicon
%V 76
%2 LBNL-44782
%8 02/2000
%! Appl. Phys. Lett.
%X <p>The craters resulting from high-irradiance (1×10<sup>9</sup>–1×10<sup>11</sup>&thinsp;W/cm<sup>2</sup>) single-pulse laser ablation of single-crystal silicon show a dramatic increase in volume at a threshold irradiance of 2.2×10<sup>10</sup>&thinsp;W/cm<sup>2</sup>. Time-resolved shadowgraph images show ejection of large particulates from the sample above this threshold irradiance, with a time delay ∼300 ns. A numerical model was used to estimate the thickness of a superheated layer near the critical state. Considering the transformation of liquid metal into liquid dielectric near the critical state (i.e., induced transparency), the calculated thickness of the superheated layer at a delay time of 200–300 ns agreed with the measured crater depths. This agreement suggests that induced transparency promotes the formation of a deep superheated layer, and explosive boiling within this layer leads to particulate ejection from the sample.</p>