I am interested in using my GF to cut some windows for IR illumination of security cameras. It seems that many kinds of black or colored acrylic are actually transparent to IR illumination for security cameras. I can buy the ludicrously expensive acrylic that advertises itself as such Or I can experiment with the black or otherwise opaque plastics offered on the GF store. Has anyone already experimented with this? If I buy some black acrylic Proof Grade will that allow IR illumination to pass through? Or not? I do understand that if it was entirely IR transparent then it wouldn’t cut on the GF at all, but I suspect that many of the colors would allow IR at wavelengths different from the laser to pass through but nobody seems to know the specifics. If nobody has already done the experiment I’ll dive in and do so, but if you have and I can save myself the money and time I’ll do that too
I think you’re on the right track, it’s probably frequency dependent…
But I will say that the CO2 laser is in the IR spectrum and it’s absorbed exceedingly well by the average acrylic. That’s why it works so well in our lasers. I strongly suspect that whatever plastic makes those black IR windows on remotes is not acrylic.
Aha, here’s a nice detailed breakdown of plexiglass transmissibility.
Have fun, data rules.
(as an economic argument, you will not even come close to matching the prices on pre-made things like this, which may not be the point for you, but anyway.
I get it, sometimes I find myself wanting to make something that would cost more than its worth in materials alone.)
You can definitely get real acrylic that is transparent more or less to IR. I assume that what they are doing is more to do with the pigment than with the plastic.
IR leds for security cameras are in the very high end of ir before it becomes not ir. I haven’t looked up the laser frequency, but since I can cut transparent acrylic I would imagine I can cut IR transparent acrylic as well since it’s the same base stuff but with a different pigment. Here is a link to the very expensive e-plastics stuff. From reading around elsewhere many people find what they need by trial and error, some pigments pass the IR others don’t. The base is still all normal acrylic though so it should be able to be cut no matter what.
but you can see those LED’s lite up as they leak a bit into the lower red range. If you want to make one that doesn’t, or want to make a lens for the camera itself that it can see through but you can’t then you need this kind of acrylic for the lens cover.
That document shows the IR spectrum, and yes as it gets closer to visible light it is more and more transparent. Laser IR is much farther down the IR spectrum. Like I said, it’ll be frequency dependent.
Opaque black is not IR transmissive. IR transmissive plastic is really a dark purple color that looks black.
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