# What would be the advantages and challenges of a UV LIDAR, sensor or designator?
**URL:** https://boards.straightdope.com/t/what-would-be-the-advantages-and-challenges-of-a-uv-lidar-sensor-or-designator/826195
**Category:** Factual Questions
**Created:** [December 15, 2018, 7:38pm UTC](https://boards.straightdope.com/t/what-would-be-the-advantages-and-challenges-of-a-uv-lidar-sensor-or-designator/826195 "2018-12-15T19:38:13Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@MichaelEmouse](https://boards.straightdope.com/u/MichaelEmouse)
#### Post date: [December 15, 2018, 7:38pm UTC](https://boards.straightdope.com/t/what-would-be-the-advantages-and-challenges-of-a-uv-lidar-sensor-or-designator/826195/1 "2018-12-15T19:38:13Z")
I often hear about radio and micro waves being used for sensing (passive or active) and designating. IR and visible spectrum are also used which much higher resolution on things like goggles, targeting pods, rangefinders, target designators etc. What about the UV spectrum?
What little I know suggests that you could have resolution equal to visible spectrum in a smaller sensor and emitter. Wouldn’t using it at night give you pretty good signal-to-noise ratio, especially at higher altitudes? Using it during the day seems like it would effectively create a lot of fog which would limit the ability of enemies to passively detect it. Is there anything I’m missing? What else could you do with it?
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [December 15, 2018, 10:22pm UTC](https://boards.straightdope.com/t/what-would-be-the-advantages-and-challenges-of-a-uv-lidar-sensor-or-designator/826195/2 "2018-12-15T22:22:41Z")
LIDAR works by measuring time-of-flight. The wavelength is pretty much unimportant.
IR emitters are vastly more efficient than UV ones, so going to UV doesn’t buy you anything.
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### Author:  [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)
#### Post date: [December 15, 2018, 10:37pm UTC](https://boards.straightdope.com/t/what-would-be-the-advantages-and-challenges-of-a-uv-lidar-sensor-or-designator/826195/3 "2018-12-15T22:37:11Z")
UV light also causes some materials to fluoresce in the visible range (teeth and white cloth, for example). Not too useful if you don’t want people to know you’re shining a UV light around. Doesn’t IR sensing work passively?
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### Author:  [@dtilque](https://boards.straightdope.com/u/dtilque)
#### Post date: [December 16, 2018, 3:30am UTC](https://boards.straightdope.com/t/what-would-be-the-advantages-and-challenges-of-a-uv-lidar-sensor-or-designator/826195/4 "2018-12-16T03:30:32Z")
> [@Ethilrist](#):
>
> UV light also causes some materials to fluoresce in the visible range (teeth and white cloth, for example). Not too useful if you don’t want people to know you’re shining a UV light around.
Certain dyes do that too. They absorb the UV and re-emit the energy in various colors. It was a fad back in the 70s to have a party iluminated by a UV light and lots of things like clothing and posters with these colors. The orange and lime-green ones are used in visibility vests.
ETA: the white cloth that fluoresces is usually because of a bluish-white dye that is in whiteners used in laundry detergents.
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### Author:  [@outlierrn](https://boards.straightdope.com/u/outlierrn)
#### Post date: [December 16, 2018, 3:38am UTC](https://boards.straightdope.com/t/what-would-be-the-advantages-and-challenges-of-a-uv-lidar-sensor-or-designator/826195/5 "2018-12-16T03:38:08Z")
> [@Ethilrist](#):
>
> UV light also causes some materials to fluoresce in the visible range (teeth and white cloth, for example). Not too useful if you don’t want people to know you’re shining a UV light around. Doesn’t IR sensing work passively?
Also semen, and most body fluids.
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### Author:  [@sitchensis](https://boards.straightdope.com/u/sitchensis)
#### Post date: [December 17, 2018, 7:27am UTC](https://boards.straightdope.com/t/what-would-be-the-advantages-and-challenges-of-a-uv-lidar-sensor-or-designator/826195/6 "2018-12-17T07:27:38Z")
For Lidar I can’t imagine a reason but it might be able to be useful for vegetation mapping. The problem is that Lidar and UV aerial photography have different goals.
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### Author:  [@scr4](https://boards.straightdope.com/u/scr4)
#### Post date: [December 17, 2018, 12:37pm UTC](https://boards.straightdope.com/t/what-would-be-the-advantages-and-challenges-of-a-uv-lidar-sensor-or-designator/826195/7 "2018-12-17T12:37:31Z")
Shorter wavelengths are more affected by scattering. So I think it would have lower signal-to-noise ratio.