Can FLIR "see" an IR laser?

[wagnerb]

I understand that "passive" Gen 3 night vision just sucks in the ambient light.

But "active" night vision blasts out either an IR laser beam or an IR floodlight, which the NV magnifies, say, on really dark nights.

My question: FLIR is "forward-looking infrared". Does that mean FLIR can "see" the IR laser or floodlight when NV (say, a PVS-14) is being used in "active" mode?

If not, why not?

 

[canucklehead]

Think of FLIR as thermal - unless the laser beam heats up whatever it's pointed at, you won't see IR laser on thermal optics.

 

[onetwentyish]

Think of FLIR as thermal - unless the laser beam heats up whatever it's pointed at, you won't see IR laser on thermal optics.

In my understanding of it that is spot on.


Op, TV-PressPass used to sell these things and could talk your ear off all day about them. Very knowledgeable guy. I will text him the link to this thread in the AM to be sure he finds it so you have a definitive answer.

 

[Suther]

I believe the difference is the wavelength of radiation. Wavelength of radiation emitted is a function of the temperature of an object.

Your "active" night vision produces near-infrared light. This is just beyond the visible spectrum of light, but many sensors that detect the visible spectrum also detect near-infrared. These wavelengths are emitted by very hot objects, like the sun. (obviously they can also be artificially produced by lightbulbs, ect)

Farther down the spectrum, you get into the longwave radiation emitted by objects at more normal temperatures(that is, temperatures we encounter here on Earth). The wavelength of this radiation (like all radiation) varies depending on the temperature of the object in question, and these differences in wavelength are what I expect the FLIR picks up.

 

[enefgee]

Some of the cutting edge FLIR stuff is pretty amazing, but the cost is too

 

[TV-PressPass]

That's a negative there OP.

Think of it this way:

All Image Intensified night vision can be active or passive. Modern units have vastly improved their passive performance, but they will all see additional illumination from infrared light sources.

So if you're using an active (ancient russian, or modern gen 1) system, and buddy is using a passive PVS-14, then you've got a spotlight shining out of your face.

FLIR is using a microbolometer to detect the surface temperature at each pixel-sized sensor, and then building a comparative image out of them. So it doesn't see light at all. Instead it's framing everything seen through its lens (germanium, not glass) and displaying that temperature difference.

So the only way to get any kind of laser to show up as an aiming point is to have that laser hot enough to start burning your target.

Does that help a little?

Suther has the right idea behind the science.

I believe the difference is the wavelength of radiation. Wavelength of radiation emitted is a function of the temperature of an object.

Your "active" night vision produces near-infrared light. This is just beyond the visible spectrum of light, but many sensors that detect the visible spectrum also detect near-infrared. These wavelengths are emitted by very hot objects, like the sun. (obviously they can also be artificially produced by lightbulbs, ect)

Farther down the spectrum, you get into the longwave radiation emitted by objects at more normal temperatures(that is, temperatures we encounter here on Earth). The wavelength of this radiation (like all radiation) varies depending on the temperature of the object in question, and these differences in wavelength are what I expect the FLIR picks up.

 

[onetwentyish]

Oops. Forgot to text TV yesterday, but he found it so it seems!

 

[geologist]

Woulda burning laser like a powerful. 6000 mW laser pointer be visible on FLIR?

 

[LeftFootOfDoom]

ok, so quick question for you tvpp.

i've used the amrys thermal nod, thats about the size of a small toaster oven, and the mount for them is designed to mate up with the laser rangefinder/designator. Do you know if that laser is visible with that thermal unit? I always assumed it would be, otherwise you wouldnt know if you were lasing the target you wanted.

 

[wagnerb]

Thank you all for these explanations.

I always thought heat and infrared radiation was a part of the electromagnetic spectrum (from radio waves through gamma radiation).

According to Wiki, "Humans at normal body temperature radiate chiefly at wavelengths around 10 μm (micrometer)", which is in the Infrared part of the spectrum.

In contrast, "Active infrared night-vision combines infrared illumination of spectral range 700–1,000 nm (just below the visible spectrum of the human eye)"

If I did the arithmetic right, FLIR looks at wavelengths of 10 micrometers, while active and passive IR look at wavelengths of 0.7 to 1.0 micrometers. Put another way, heat given off by humans has ten times the wavelength of the IR laser used in active nightvision. So the same piece of equipment will not pick up both wavelengths. FLIR won't pick up active IR. Unless, of course (as some posters noted), the active IR laser warms up the thing illuminated.

Thank you for focussing me on this problem, guys.

 

[TV-PressPass]

ok, so quick question for you tvpp.

i've used the amrys thermal nod, thats about the size of a small toaster oven, and the mount for them is designed to mate up with the laser rangefinder/designator. Do you know if that laser is visible with that thermal unit? I always assumed it would be, otherwise you wouldnt know if you were lasing the target you wanted.

Almost certainly there's a "laser active" marker in the hud of the device that alerts the user. Similar to the "IR active" light in your basic PVS-14.

But my experience with laser designators has been extremely limited. Like literally: 30 seconds. We saw the hot-spot, the user told me it was a challenger, he ranged it, beamed it, then we saw the "I'm hit" flashers go off.