Buying a Laser Pointer: What Can It Do?

[brewAP2010]

I recently bought a laser pointer offline, it claims to be able to reach up to 12 miles, and from what I can tell it is pretty strong. It says the max output power is < 5mW, and the wavelenght is 532nm. Its just a regular laser pointer, and I was wondering if there are lasers that you can buy (legally) that could like burn through stuff, or maybe pop balloons or something cool like that? And what does the wavelength only affect the color or does it play a factor in the actual strength of the laser?

 

[NobodySpecial]

I recently bought a laser pointer offline, it claims to be able to reach up to 12 miles

It reaches for ever if you have a good enough detector!

Its just a regular laser pointer, and I was wondering if there are lasers that you can buy (legally) that could like burn through stuff, or maybe pop balloons or something cool like that?

Depends where you live, importing laser pointers > class I (ie more than 5mW) into the US is restricted.

And what does the wavelength only affect the color or does it play a factor in the actual strength of the laser?

The wavelength is the color, the brightness you get at a particular power depends on the color because it depends on the sensitivity of your eye - that's why green looks so bright.
The power you can get at each wavelength also depends on engineering details

 

[Danger]

I will mention something here that some people might not realize, since it has been done as a "joke" in the past. DO NOT EVER AIM ONE OF THOSE THINGS AT AN AIRCRAFT! Not only is it stupid and dangerous, but it is also considered an act of terrorism in both the US and Canada. You can be locked up for the rest of your life if caught.

 

[Dr Lots-o'watts]

... And what does the wavelength only affect the color or does it play a factor in the actual strength of the laser?

Wavelength and power are independent. Some manufacturers may provide the curve of power vs wavelength.

From the FDA site: "Consumer laser products are generally in classes I, II, and IIIa"
http://www.fda.gov/Radiation-Emitti...ent/LaserProductsandInstruments/ucm116362.htm

 

[hl_world]

5mW isn't strong for most lasers sold as "pointers" but it is decent for use as one to point at near objects. Burning lasers are in the 100s of milliwatts range but it also depends on the type of laser (wavelength, beam diameter, divergence). Divergence means the beam is more in the shape of a long cone than a cylinder so it's light concentration varies with distance from the laser. Green lasers have a tighter beam so their power is more concentrated. Red lasers have a wider beam and it diverges more so it needs to be focused to a smaller point with a lens like you would with sunlight and a magnifying glass.

The color of the beam itself is also important to what you want to burn. When light shines on an object, it absorbs some wavelengths and it heats up but it also reflects other wavelengths and the reflected light is what determines its colour. Another reason you'll want it to reflect less is that you don't want any of that light in your eye (always wear goggles anyway). A light blue object will absorb redder wavelengths from white light and reflect the rest so a 650nm laser will burn it more efficiently. A purple object will absorb green wavelengths and reflect red and blue wavelengths from both ends of the spectrum so a 532nm laser would be best there. Black objects absorb all the light so it's ideal for any laser.

A little more info about the colour of the beam: "Blue" lasers rated at 405nm are actually a violet colour and at the same power rating, they are a lot dimmer than green lasers but are more dangerous. The eye detects wavelengths at different efficiencies.

 

[Pianoman14]

I recently bought a laser pointer offline, it claims to be able to reach up to 12 miles, and from what I can tell it is pretty strong. It says the max output power is < 5mW, and the wavelenght is 532nm. Its just a regular laser pointer, and I was wondering if there are lasers that you can buy (legally) that could like burn through stuff, or maybe pop balloons or something cool like that? And what does the wavelength only affect the color or does it play a factor in the actual strength of the laser?

1) Yes you can buy them, generally online. You will need >80mW to burn things, though. Snooping inside of packages is rare, so there is a good chance it will get to you. A quality manufacturer is www.dragonlasers.com[/url]. If you are interested in these things at all, check out [url]www.laserpointerforums.com[/URL].

2) Wavelength only affects colour.

Wear safety goggles, and have fun!

 

[Dr Lots-o'watts]

Depending on your projects, you may have use for one of these:
http://gentec-eo.com/products/power-detectors

 

[Danger]

I sometimes wonder if I'm the only guy with a nostalgic love for the ruby pulse laser. I learned how to build one of those in 1968, and it's still my favourite.

 

[NobodySpecial]

I sometimes wonder if I'm the only guy with a nostalgic love for the ruby pulse laser. I learned how to build one of those in 1968, and it's still my favourite.

Or the famed 'Gin and tonic' laser - http://www.opnmagazine-digital.com/opn/200905/?pg=16#pg16

 

[Danger]

Or the famed 'Gin and tonic' laser - http://www.opnmagazine-digital.com/opn/200905/?pg=16#pg16

That looks like an interesting article, but right now I have my "Accessibility" settings turned off, so I can't read it. After I'm through with PF for the night, I'll reset them and revisit the post with the text expanded.

 

[brewAP2010]

DO NOT EVER AIM ONE OF THOSE THINGS AT AN AIRCRAFT! Not only is it stupid and dangerous, but it is also considered an act of terrorism in both the US and Canada. You can be locked up for the rest of your life if caught.

I actually read something about a guy that did that and the authorities found, and arrested him, so I'm pretty cautious about shining it in the sky.

 

[brewAP2010]

1)

2) Wavelength only affects colour.

That's what I thought, but then do they make them different colors to denote the strenght of the laser even though it is unrelated?

 

[brewAP2010]

5mW isn't strong for most lasers sold as "pointers" but it is decent for use as one to point at near objects. Burning lasers are in the 100s of milliwatts range but it also depends on the type of laser (wavelength, beam diameter, divergence). Divergence means the beam is more in the shape of a long cone than a cylinder so it's light concentration varies with distance from the laser. Green lasers have a tighter beam so their power is more concentrated. Red lasers have a wider beam and it diverges more so it needs to be focused to a smaller point with a lens like you would with sunlight and a magnifying glass.

The color of the beam itself is also important to what you want to burn. When light shines on an object, it absorbs some wavelengths and it heats up but it also reflects other wavelengths and the reflected light is what determines its colour. Another reason you'll want it to reflect less is that you don't want any of that light in your eye (always wear goggles anyway). A light blue object will absorb redder wavelengths from white light and reflect the rest so a 650nm laser will burn it more efficiently. A purple object will absorb green wavelengths and reflect red and blue wavelengths from both ends of the spectrum so a 532nm laser would be best there. Black objects absorb all the light so it's ideal for any laser.

A little more info about the colour of the beam: "Blue" lasers rated at 405nm are actually a violet colour and at the same power rating, they are a lot dimmer than green lasers but are more dangerous. The eye detects wavelengths at different efficiencies.

ok I didn't know that thank you so much.

 

[cjl]

That's what I thought, but then do they make them different colors to denote the strenght of the laser even though it is unrelated?

Nope. You can get strong or weak lasers in any of the available colors, though some are easier to make than others. Also, at a given power, green lasers will look the brightest, since they are the color your eye is most sensitive to.

 

[brewAP2010]

Ok thanks...yea the one that I have seems to be super bright. If I shine it on like a white wall its almost hard to look at, and what's pretty cool is that when it is dark enough you can see the entire beam.

 

[cjl]

Yep - a 5mW green laser pointer will be very, very bright, while a 5mW red will seem relatively dim. A 5mW violet (405nm) laser is quite dim, dimmer even than the red (even though all of them are outputting the same amount of power).

 

[brewAP2010]

ok thanks a lot for the help