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I can’t say I have any experience with PVS-14 or any Night Optical Devices, but from what I see online, it amplifies certain visible spectrum as well as near-IR. It doesn’t seem to rely on IR much. And red dot sights aren’t even IR are they? At least not entirely, cause you can see them with the naked eye.
Regarding glass being opaque to IR, apparently, it depends on the type of glass. I just remembered it from a Vsauce video (IIRC) where it was demonstrated to be opaque. But since term IR is vague and doesn’t have super defined borders, and there are different types of glass, yeah, it’s not a certain statement.
I’m sorry if I made the false impression that I know what I’m talking about. I’m just discussing and learning as I go. But I went back to the article and looked for the specific figures, and you were right, they are amplifying 1550-nm wavelength, which is NIR. And average glass is usually opaque to wavelength at around 2500nm, so it shouldn’t get blocked. At least not much.