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Physics Project

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tron23

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Hi guys, I'm new to electronics even though I have a tendency of taking apart electrical objects.  ;)
My friends and I are planning to build a burning laser for a physics project. I just want to get an idea of what we're going to do since, none of us have the slightest idea of how a laser works or how to build one. We also don't have any electrical experience, so I hope that's not a real big issue  :'(  
Also I was wondering if I could build my laser with a diode from my old laptops cd drive. Thanks in advance.  
 





Tw15t3r

Tw15t3r

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Welcome to the laserpointerforums. Glad that another has joined and and shares interest with all of us here.

I'll cover the questions that are not so common around here, but for the rest of your questions, just read the stickys and threads around here and there. You will learn alot more than I can explain in one post.

For how a laser works, check wikipedia, or take this short and simple explanation: a typical laser uses some energy (be it electrical, optical or chemical) to excite a medium, eg. HeNe laser has Helium and Neon as the medium, which causes the electrons in the inner shells to jump to the outer shells of the atoms. Upon returning to the inner orbits, they emit light which under certain conditions produce the laser.

The lasers we mostly are building in this forum are diode lasers which uses electrical energy to move electrons from their shells into the circuit leaving holes in the silicon. Other electrons fall into these holes giving off laser light under the right conditions.

Electrical experience would be good, or actually, it is electronics experience that is needed here. But do not worry if you have neither, for there are step by step guides in this forum that you can follow.

Also, a CD drive, even if it is a burner, would be too weak for a laser. You need to get a DVD-RW drive, preferably 16x and above. Most are using 22x drives for the best burning power.
 
pullbangdead

pullbangdead

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Tw15t3r said:
Welcome to the laserpointerforums. Glad that another has joined and and shares interest with all of us here.

I'll cover the questions that are not so common around here, but for the rest of your questions, just read the stickys and threads around here and there. You will learn alot more than I can explain in one post.

For how a laser works, check wikipedia, or take this short and simple explanation: a typical laser uses some energy (be it electrical, optical or chemical) to excite a medium, eg. HeNe laser has Helium and Neon as the medium, which causes the electrons in the inner shells to jump to the outer shells of the atoms. Upon returning to the inner orbits, they emit light which under certain conditions produce the laser.

The lasers we mostly are building in this forum are diode lasers which uses electrical energy to move electrons from their shells into the circuit leaving holes in the silicon semiconductor.  Lasers and LEDs use other semiconductors, not silicon.  Other electrons fall into these holes giving off laser light under the right conditions.

Electrical experience would be good, or actually, it is electronics experience that is needed here. But do not worry if you have neither, for there are step by step guides in this forum that you can follow.

Also, a CD drive, even if it is a burner, would be too weak for a laser. You need to get a DVD-RW drive, preferably 16x and above. Most are using 22x drives for the best burning power.  A CD burner will also use an IR diode, which will be nearly invisible (so not as much fun, in some ways) while still being very dangerous to your eyesight (yeah, it can blind you even though you can't see it).  As mentioned, get a DVD burner diode, DVD uses red laser light.  For an even cooler burner, get a Blu-ray/blu-ray burner diode, which emits violet/purple laser light.
Click to expand...


Corrected a couple things.  Also, if you're going to be making/using/"playing with" powerful laser diodes such as those in DVD burners, you should REALLY consider protective eye wear.  So in addition to reading the stickies in each section, especially the stickies in this one (Tutorials/Help/Repairs), take a good, long read through the Safety section.
 
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Ace82

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I'm not sure using lasers as your physics project is a good idea.  yeah, they're cool and they use physics, but they are dangerous and you don't want to risk everyone with eye damage, meaning that any laser over 5mW (as a general rule of thumb) should not be used without the proper laser's wavelength goggles.  And I don't think you will be spending $30-60 dollars a pop for everybody to wear them.  

If you want to use lasers in your physics project, then you should consider using diagrams and video.  You should explain about the power, (milla watts) and [highlight]the application vs wavelength vs time vs surface[/highlight], without actually showing a laser in action.  Everybody's seen the 5mW reds, maybe a 5mW green would be cool to show people, then you could even get into the explanation of DPSS, which isn't used in data storage.  What I mean about what I highlighted above, for example:

CDR - uses IR laser burns at what speed is how many mW and can store so much info on one disk
DVDR - uses 650nm red laser at what speed is how many mW and can store so much info on a different type of disk (oh yeah, different surfaces absorb the different wavelengths differently)
blu-ray - uses 405nm....

and so on.  But it's your project so you do the research!  ;)  That should get you an A.   :)
 
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tron23

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Thx guys. I read around the forums and realized the dangers of lasers. I just might call it off, but I was wondering about the minimal amount of mW needed to have a laser burn matches and pop balloons. Also instead of getting goggles, is there a way of making a box to contain the laser so it wont damage our eyes? thx  
 
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