I am designing an IR Blaster enclosure, i want to know which material to use in the mould, we explored polycarbonate with black pigments but it limits the blaster strength. I need to know if there are any special composition which can provide a clear path to ir signals and blocks the circuit to be visible from outside. There are sample images as below for the desired output. Thanks in advance.

 

I've seen deep red and purple plastic used for the windows of IR senders and receivers. It looks black until you shine a light through it.

 

I've seen deep red and purple plastic used for the windows of IR senders and receivers. It looks black until you shine a light through it.

I understand that, but for manufacturing purposes we need the exact material and pigment name/type.