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what are nm?

1Nick

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ive been online looking for a new laser. i noticed that some 120mw lasers are more expensive than a 200mw because of the nm. can someone tell me why this is and what do the nm do to the laser? does it make it burn better? also, wha does nm mean? thanks, nick.
 

Prototype

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An 'nm' is a nanometer (1.0 x 10^-9) and it determines the wavelength of the laser, 650nm is red, 532nm is green (and near the peak of human eye-sensitivity), 473nm is blue, 405nm is a violet shade. Green lasers cost more because they're DPSS, as are blue lasers, but are far less inefficient.
 
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Nano meters. itis the unit of measurement of seeing colours in the spectrum.it classifies the colour of the laser Eg Green is 532nm.
use the search button.
cheers
 

1Nick

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lol, okay. thanks. so all the nanometers mean is just the original color? i dont get why they just say "red IR filtered laser." lol, thanks guys
 
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Unless they're talking about a DPSS red laser like 671nm then they just have no idea what they're talking about.
 
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lol, okay. thanks. so all the nanometers mean is just the original color? i dont get why they just say "red IR filtered laser." lol, thanks guys

Some lasers, called DPSS, use an IR diode to make the color. Because of this the lasers output can be mixed with the IR. IR is invisible, so you wont see it.

The problems of IR mixing with the colors are
1. It can give false power readings. If you buy a 200mW DPSS laser, and 150mW comes from IR, then you are not getting the full 200mW of color.
2. Because IR is invisible, if you caught a stray beam it will damage your eyes because you cant see it. Also if it did not have a filter, you would need goggles to protect you from the IR, along with goggles to protect you from the original color.

This is how companies produce cheap lasers. As stated above, a 200mW laser that is only producing 50mW of color is garbage. The better lasers have an IR filter, and produce a much higher color power. So the beams are brighter, and can burn more stuff.

The good thing is that IR filters are cheap, and somewhat easy to install. The bad part is if you have a cheap laser, it will cut the power in half in most cases. You want to buy from a company a laser that gives you a power reading with the filter.

The IR diode is referred as a pump diode in the diagram.

 
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Nice link! I have a chart handy as well which shows the eye's sensitivity of the various wavelengths:
 

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Crazy Jay

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1Nick.. depending how long or short the wave of light is .. determines its color. Red is more spaced out while green is going to be shorter or tighter. You measure this with nanometers which is one billionth of a meter

Tiny right?
 

chipdouglas

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lol, okay. thanks. so all the nanometers mean is just the original color? i dont get why they just say "red IR filtered laser." lol, thanks guys

also standard diode lasers (not dpss) do not emit ir because they are a single wave length....


michael
 

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But yellows are very expensive and are usually a combination of a red and green beam.
Yes, they are expensive but no, they aren't "usually a combination"; most of the 589nm lasers we talk about around here are DPSS (and most have been purchased by way of a Glenn CNI GB :wave:)
 

1Nick

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1Nick.. depending how long or short the wave of light is .. determines its color. Red is more spaced out while green is going to be shorter or tighter. You measure this with nanometers which is one billionth of a meter

Tiny right?
damn, that is small!
 




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