I need to block the 'faint glow', which is to say red light noise, of an 850nm-IRLED IR floodlight.
Since green absorbs red, and acrylic transmits IR, natural approach seems to be to use a sheet of green transparent acrylic in front of the light. That correct?
(I'm aware there are 940nm-IR floodlights out there. For some reason, they are hardly available in Germany though.)