High performance optical edge and laser-line filters and methods of making
the same are disclosed. The optical edge filters have an edge steepness
greater than about 0.8% as measured by dividing (a) the edge width from
the 50% transmission wavelength to the optical density 6 ("OD6")
wavelength by (b) the 50% transmission wavelength. The optical edge
filters also have an average transmission above about 95%. The laser-line
filters have an extremely high transmission in the passband (greater than
90%), an extremely narrow transmission bandwidth, and achieve blocking
with an optical density (OD) greater than 5 at wavelengths that differ
from the laser wavelength by less than 1% of the laser wavelength. The
methods for making such filters accurately determine when deposition of
each layer of the filter should terminate.