Order blocking filter: Thorlabs FGL400S
The optional FGL400S is a 2-inch-square colored-glass longpass filter. It
attenuates wavelengths below approximately 400 nm. This suppresses
short-wavelength light that would otherwise contaminate the first-order spectrum
at roughly twice its wavelength.
Property |
Value |
|---|---|
Filter type |
Colored-glass longpass |
Glass |
Schott GG400 |
Nominal edge |
400 nm |
Form factor |
Unmounted 50.8 mm × 50.8 mm square |
The filter is easily removable because it trades suppression of higher-order blue light against additional absorption and surface losses. Its measured transmission curve should be accounted for when it is included in throughput calculations.