What type of IR or infrared light can pass through glass?

Question

I always assumed that infrared light cannot pass through glass. But, I took my TV remote control, held down a button, placed the IR sender behind a drinking glass, but still detected the IR light with my digital camera on the opposite side of the glass (could see the IR flashing). Was it because the TV remote's IR wavelength was too short?

I also wonder about thermal imaging which detects the lower range of infrared. If someone is standing behind a window at night and you point a thermal imaging device at the window, can it detect the person's body heat through the glass?

Thanks. I love physics.

Answer 1

actually, it all depends on the wavelength of the IR.
Near IR can go trough glass like the visible till around 1.5µm.
Glass absorbs at around 3µm and up. Thermal imaging detects wavelengths around 10µm, so you won't detect anything behind a glass.

Answer 2

Ir Passthrough

Answer 3

Yes, Infrared wavelengths will pass through glass. Glass starts attenuating radiation in the UV range.

Answer 4

was once an infra purple filter out glass made via twist of destiny. do no longer comprehend in the event that they are nevertheless around.Infra purple filters are additionally used in photos, and infrared filters have been often equipped interior the nostril cone of arc lamps and have been often composed of quite a few glass strips. I understand that a similar type of shape exists on wood burning stoves, yet not sure in the event that they might go with to be an infra purple filter out.

Answer 5

If you ever do spectrophotometry, you'll see that glass and quartz cuvets are actually used for UV-vis radiation. So IR can definitely pass through glass. Typically, for visible light and IR you use plastic cuvets b/c they don't cost $50 (quartz ones cost that much EACH) and they allow radiation to pass through, but yes... that doesn't mean glass won't.

Answer 6

infared can go through glass