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296 So l i d - S t at e La s e r s Heat-Capacity Lasers 297

Figure 11.32 25 kW on a 1-in-thick carbon steel target for 10 s.

Figure 11.33 Laser interaction of a thin-walled aluminum sheet with airflow; 0.07 s
total elapsed time.

size), softening it to the point at which initiation of a crack and the
ultimate rupture of the material occur. A high rate of airflow is
directed across the surface to simulate flying through the atmosphere.
This experiment demonstrates that well before melting of the
aluminum sheet, the material softens and bulges outward due to
the low-pressure region formed by the flowing air. The hydrody-
namic force generated by the stream of flowing air is sufficient to
rip away the thin aluminum skin. This aerodynamic imbalance
either destroys the structural integrity of the target or sends it off its
desired flight path.

11.6.3 Laser Used for Humanitarian Mine Clearing
In 2004, the Lawrence Livermore National Laboratory received a
12
Research and Development 100 award for developing a heat-
capacity laser for use in humanitarian mine clearing. Experiments
showed that due to the laser system’s pulsed format, the laser beam
could bore through soil at a very fast rate, heat up a buried land
mine in seconds, and raise the temperature of the high explosive
within the land mine sufficiently for deflagration to occur.