Fig. 1.

Schematic drawing of the laser exposure setup for the determination of porcine skin damage thresholds at the wavelength of 1319 nm. The $1/e^2$ beam diameter arriving at the focusing lens was about 1.20 cm, and the selected $1/e^2$ beam diameters were measured to be $0.98\pm 0.01$ and $1.96\pm 0.02\mathrm{cm}$ at two target planes by repeated measurements prior to exposure. The distances between the lens and the target planes with the two spot sizes (0.98 and 1.96 cm) were about 108.2 and 161.3 cm, respectively.