
390
Laser-Induced Damage in Optical Materials
coating material yield strength, leading to a complete delamination of the blistered lm.
Nondelaminated at-bottom pit blistering has been observed at subejection thresh-
olds, adding validity to the proposed damage mechanism. Flat-bottom pits are typi-
cally no deeper than three layer pairs because of the rapid decay of the SWEF strength
and the increase in the mechanical durability of the lm with increasing thickness.
0
20
10
30
40
50
–0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
Air
L
H
Sub
FIGURE 14.4 S-polarized standing wave electric eld ...