Long & Short Pass Filters
Long-pass
and short-pass filters are useful for defining spectral regions or as dichroic
beamsplitters. These are thin film
filters deposited onto BK7
or UV Fused Silica
substrates. They are arranged to
have a very sharp cut-off. However,
the reflection region is limited so it is important to specify clearly the
rejection wavelength range required. Normally
high reflection and high transmission wavelengths should be separated by at
least 100nm.
Cut-off
points can be selected in the range 400
to 1000
nm
in 50nm
increments.
These
filters are circular in shape. Diameters are: 25.4 and
50.8 mm ( 1” and 2”).
Thickness
is 1.5
mm
for the 1” diameter filters and 2.0mm for the 2” diameter filters.