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View Full Version : Question about 906NM (IR) laser and the best absorbant color



StlouisX50
10-21-2005, 01:18 AM
I have been looking at buying a new vehicle, I have always been told from the begining of time , that black is the best color to absorb light. However I have recently read that is only true to the visable light spectrum. What I could not find out further was what was the best color for absorbing IR light such as the 906nm laser beam.

The information in regards to black being the best only to visable light was from a creditable source, on scientific site.

TexasRed
10-21-2005, 02:43 PM
Isn't it 904 nm?

Veil Guy
10-21-2005, 03:35 PM
Black is very likely the best color for IR as well.

Shape is also very important. The pointier, the better.

Stay away from metallic flecked paint, too. This type of paint essentially contains thousands of "mirrors."

Veil Guy 8)

boxster
10-22-2005, 05:58 AM
1. The laser guns in the USA use 904 nanometers of near infrared radiation. You could use other wavelengths. They may in Europe. Someone else will have to answer that tech question.
2. The wavelength names of radiation around 904 nm are: UV, Visible and Near IR.
3. The wavelengths for UV are 200 to 400 nanometers
4. The wavelengths for Visible are 400 to 700 nanometers
5. The wavelengths for Near IR are 700 to 2500 nanometers
6. Regular IR is beyond 2500 nm and everyone knows that as heat.
7. Carbon black, mainly the blackest black that is dull (no shine), such as the soot found in a furnace flue. This absorbs the UV, Visible and the Near IR. So regadless of wavelength 900 or 904 or 1010 nm, black will absorb all of these.
8. Other dark colors work pretty good at absorbing Near IR, but the more towards flat black the better.
9. This carbon black is called a black body radiation absorber. If you look in a general physics book you will see this term.
10. Ever notice how black things get really hot in the sun? That is becasue they are absorbing UV, Visible and IR and converting them from that form of radiation into heat energy. White or aluminum minimize this effect becasue they are reflectors. Metal flake paints also reflect radiation.
11. As for shape, you want to avoid any vertical surfaces. It is like a Stealth fighter jet, flat black and minimal reflective surfaces to bounce energy off.

Hope that helps clarify :shock:

jimbonzzz
10-22-2005, 07:17 AM
904nm +/- 10 is the specs they usually publish in the manual, but the actual laser diode they use is centered at 905nm, so I'm not sure why they publish 904. It might be that they use a photodiode detector with a spectral filter that the is centered slightly lower which brings the overall optimal operating wavelength down slightly, just a guess though...

Jim

zappy
11-10-2005, 12:26 PM
Flat black is best, albeit ugly and not available from any car manufacture. Black absorbs IR the same as any other light. Touch a black car in the summer, feel the heat, that's IR energy.