
358
Laser-Induced Damage in Optical Materials
quickly at a high-index half-wave layer inserted in between the two existing quarter-
waves. An index of around 2.15 is good and corresponds to a material like tantalum
pentoxide. Figures 13.8 and 13.9 show some calculated results.
e V-coat based on two quarter-wave layers demands accurate indices of refraction
for the layers that must satisfy Equation 13.25. is is a serious limitation because we
do not have a continuous set of indices available since they are tied to our preferred
materials. However, it can be shown that for a normal range of indices, provided that
y
L
2
/y
0
lies between y
sub
and y