2x10 (a N=1051=100mw/cm2 1x10 2x10[(b) N=10°1=100mw/cm2 1x10 8x10 19 N=10°1=01mw/cm2 4x1091 0 AW 0 500 1000 1500 20005 2 N I = = 10 100 mw / cm 6 2 N I = = 10 100 mw / cm 6 2 N I = = 10 0.1 mw / cm