How Does A Laser Work?

P-KhanP-Khan Join Date: 2003-05-27 Member: 16776Members
I've seen that several of the NS forum memebrs are quite smart people, so I'v gotta ask this question.

How can I make a laser? One that can cut through paper, not just a beam of light.

Comments

  • raz0rraz0r Join Date: 2003-07-24 Member: 18395Members
    i never actually thought about it, and i just realised i have no idea whatsoever and if i were to take a random guess, id say:

    'nanites'
  • CommunistWithAGunCommunistWithAGun Local Propaganda Guy Join Date: 2003-04-30 Member: 15953Members
    <!--QuoteBegin-P-Khan+Apr 15 2004, 10:58 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (P-Khan @ Apr 15 2004, 10:58 AM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin--> I've seen that several of the NS forum memebrs are quite smart people, so I'v gotta ask this question.

    How can I make a laser? One that can cut through paper, not just a beam of light. <!--QuoteEnd--> </td></tr></table><div class='postcolor'> <!--QuoteEEnd-->
    A ruby diode
  • DreadDread Join Date: 2002-07-24 Member: 993Members
    Well, afaik laser is just a concentrated beam of light so...
    a) Get black paper
    b) Burn through it with a magnifying glass <!--emo&:)--><img src='http://www.unknownworlds.com/forums/html//emoticons/smile.gif' border='0' style='vertical-align:middle' alt='smile.gif' /><!--endemo-->
  • CyndaneCyndane Join Date: 2003-11-15 Member: 22913Members
    Any kind of paper will work, size shape and or color doesn't matter, and as for the magnifying glass, well make sure you create a really really really tiny circle, thus it becomes a focal point. Much like laser pointers work, a bunch of reflective lenses concetrating light from either an LED or a bulb, though I haven't seen a portable "cutting laser" yet. :-)
  • MedHeadMedHead Join Date: 2002-12-19 Member: 11115Members, Constellation
    edited April 2004
    <a href='http://www.techtv.com/screensavers/modtips/story/0,24330,3440290,00.html' target='_blank'>Laser cutters</a> are <a href='http://www.ulsinc.com/english/laser_systems/laser_systems.html' target='_blank'>very expensive</a>. There are those that are <a href='http://www.versalaser.com/' target='_blank'>cheaper</a>, but I don't think you can expect to be able to <a href='http://www.argelas.org/s0_body.htm' target='_blank'>manufacture</a> one in your <a href='http://xenia.media.mit.edu/~yarin/laser/' target='_blank'>basement</a> that doesn't have the possibility of <a href='http://www.sgi.com/grafica/lasercut/index.html' target='_blank'>exploding in your face</a> or costing you quite a bit. Unless of course you're just wanting to burn paper and nothing else. In that case, <a href='http://www.eio.com/public/lasers/index.html#229' target='_blank'> there are others like you</a> who might be able to <a href='http://www.repairfaq.org/sam/laserfaq.htm' target='_blank'>help.</a>
  • ZaphodZaphod Join Date: 2003-12-30 Member: 24882Members
    How much would you like me to go into this?
    As for *making* a laser, your best bet is to buy one.

    How a laser works:
    If you've had some intro Chem or Physics, you might know that atoms have discrete energy levels (ie. 1s, 2s, 2p if you remember these). What happens is that the electrons of the atom 'jump' to higher energy levels when excited.
    So, if a electron is hanging around at some energy level and a photon (light) is absorbed by the atom, the electron can jump to a higher energy level (depending on the energy of the absorbed photon).
    Lasers usually excite atoms by 'pumping' with a pulsed electric field. For the most part, all atoms in the laser (some lasing chamber) are all the same type of atoms so that they all will get excited to the same energy state when pumped.
    So now we have a chamber w/ a bunch of excited atoms. Now what will happen is that the electrons will relax or fall back into a lower energy state, and when that happens, a photon is emitted that has the same energy as the difference between the 2 energy states. Since all the atoms are the same, this means that all the photons emitted will have the same energy, which means that all the light emitted has the same wavelength (color). The photons bounce back and forth in the lasing chamber (which has very specific types of mirrors on the ends), and the photons are released from one end, making your laser beam.


    The End


    Hope this makes sense... I can explain more if needed.
  • RPG_JssmfulhudRPG_Jssmfulhud Join Date: 2002-11-02 Member: 4006Members
    <!--QuoteBegin-CommunistWithAGun+Apr 15 2004, 06:15 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (CommunistWithAGun @ Apr 15 2004, 06:15 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin--> <!--QuoteBegin-P-Khan+Apr 15 2004, 10:58 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (P-Khan @ Apr 15 2004, 10:58 AM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin--> I've seen that several of the NS forum memebrs are quite smart people, so I'v gotta ask this question.

    How can I make a laser? One that can cut through paper, not just a beam of light. <!--QuoteEnd--></td></tr></table><div class='postcolor'><!--QuoteEEnd-->
    A ruby diode <!--QuoteEnd--> </td></tr></table><div class='postcolor'> <!--QuoteEEnd-->
    Get that, flash it a few times and you'll be on your way. Doubt you'll be able to cut things though. <!--emo&;)--><img src='http://www.unknownworlds.com/forums/html//emoticons/wink.gif' border='0' style='vertical-align:middle' alt='wink.gif' /><!--endemo-->
  • DragonMechDragonMech Join Date: 2003-09-19 Member: 21023Members, Constellation, Reinforced - Shadow
    <a href='http://science.howstuffworks.com/laser.htm' target='_blank'>www.howstuffworks.com</a> - your one-stop shop for surprisingly useful info.
  • tommydtommyd Creator of ns_tanith, co_pulse and co_faceoff Join Date: 2002-01-24 Member: 40Members, NS1 Playtester, Contributor, NS2 Developer
    /me works as a US Army laser researcher and i still don't know.
  • BogglesteinskyBogglesteinsky Join Date: 2002-12-24 Member: 11488Members
    edited April 2004
    Zaphod's explanation is basically correct. The important thing is that the electrons all return to thier normal state at the same time. This way, the photons emmited are in phase, making the laser much more powerful.

    LASER stands for Light Amplification by Stimulated Emission of Radiation. The name basically explains it. The "Radiation" is light radiation, not glowy green stuff.
  • LikuLiku I, am the Somberlain. Join Date: 2003-01-10 Member: 12128Members
    A laser wouldn't cut paper, it'd just burn it. Right?
  • tommydtommyd Creator of ns_tanith, co_pulse and co_faceoff Join Date: 2002-01-24 Member: 40Members, NS1 Playtester, Contributor, NS2 Developer
    if you put your hand in front of a ~1.55um laser that runs at >1mJ/10Hz (non eye safe) you can actually 'feel' the laser pulse even tho u cant see it. ive done it before, it's fun.
  • NecrosisNecrosis The Loquacious Sage Join Date: 2003-08-03 Member: 18828Members, Constellation
    Unfortunately since its using a lot of energy to punt electrons around, lasers tend to be power hungry, and most of the beams strength will be lost to surrounding air.

    Hence really big lasers are very very expensive and woefully inefficient.
  • big_jimbig_jim Join Date: 2003-12-14 Member: 24350Members
    during freshers week at my university, one of the "example" lectures and demonstartions in my department (physics and astronomy) was from the laser physics researchers.

    as a demonstration they wheeled out the CO2 laser they use in the labs, and burnt a hole through (as well as setting fire to) a piece of wood 4 inches thick in about 10 seconds.

    and that was quite a weak CO2 laser.
  • XythXyth Avatar Join Date: 2003-11-04 Member: 22312Members
    You guys are talking about how much energy it takes, perhaps you could use a large cap bank to power it? Though it wouldn't be a constant beam, more like a quick flash of it.

    If you are really just looking for a cool thing to build for fun or like a science fair, make a railgun or coilgun, very fun, high possibility of electricuting yourself(part of the fun factor), and potentially very powerful. Im making a coilgun myself ffrom a bunch of disposable camera flashes, it's teh kewl.
  • ZaphodZaphod Join Date: 2003-12-30 Member: 24882Members
    Yea, there are tons of projects you can do that are tons of fun.
    My friends and I made a Trebuchet as a part of our Physics Club. 16 foot arm w/ up to 1300 lbs of counterweight <!--emo&:D--><img src='http://www.unknownworlds.com/forums/html//emoticons/biggrin.gif' border='0' style='vertical-align:middle' alt='biggrin.gif' /><!--endemo-->
    I'm about to start working on making my own 10" telescope, I'm just waiting for my mirror blank to get in so I can start grinding it down.
    Another project I've been meaning to do is make a small turbine engine using an old turbocharger. Very simple idea, just takes some work.
    Another quick and cheap project is making a potato gun. I have one made out of ABS (like PVC but black and not pressure-rated) that I use Right-Guard Deodorant as a propellant.
  • XythXyth Avatar Join Date: 2003-11-04 Member: 22312Members
    Yeah there is just somthing about building your own weapons <!--emo&:D--><img src='http://www.unknownworlds.com/forums/html//emoticons/biggrin.gif' border='0' style='vertical-align:middle' alt='biggrin.gif' /><!--endemo-->
    I used to make crossbows and stuff from knex (The good ol days).
    Made a rocket sorta lancher from bottle rockets and a big piece of pipe. Also made a nice taser that goes to 990 volts (and it goes without saying that I managed to shock myself with it <span style='font-size:8pt;line-height:100%'>on purpose</span>). I've been contemplating a potato type cannon that instead launch soda cans, and right now im working on my coilgun that is being made fro the scavenged parts of that taser.
  • XiileXiile Join Date: 2003-02-22 Member: 13818Members
    <!--QuoteBegin-Xyth+Apr 15 2004, 02:53 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (Xyth @ Apr 15 2004, 02:53 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin--> Yeah there is just somthing about building your own weapons <!--emo&:D--><img src='http://www.unknownworlds.com/forums/html//emoticons/biggrin.gif' border='0' style='vertical-align:middle' alt='biggrin.gif' /><!--endemo-->
    I used to make crossbows and stuff from knex (The good ol days).
    Made a rocket sorta lancher from bottle rockets and a big piece of pipe. Also made a nice taser that goes to 990 volts (and it goes without saying that I managed to shock myself with it <span style='font-size:8pt;line-height:100%'>on purpose</span>). I've been contemplating a potato type cannon that instead launch soda cans, and right now im working on my coilgun that is being made fro the scavenged parts of that taser. <!--QuoteEnd--> </td></tr></table><div class='postcolor'> <!--QuoteEEnd-->
    I would kill to be able to do that.
  • weggyweggy Join Date: 2003-06-04 Member: 16998Members
    I have built the soda can gun. Good fun. Its awesome how they explode when you shake em up and shoot them at trees.

    Theoritically, a laser can be as strong as you want it to be. So theoretically, if you put a nucler reactor behind a laser, you could blast a bunker, or something.

    Im by no means an expert on it.

    <!--QuoteBegin--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> </td></tr><tr><td id='QUOTE'><!--QuoteEBegin-->/me works as a US Army laser researcher and i still don't know.<!--QuoteEnd--></td></tr></table><div class='postcolor'><!--QuoteEEnd-->

    Lol
  • P-KhanP-Khan Join Date: 2003-05-27 Member: 16776Members
    Well, I was gonna get the Science Dept. laser, and destroy it to make one which can cut through paper, as it's my Extended Essay thesis for the IB. Their laser only produces a light beam.

    I just need to know how to intesify the heat to cut through paper. And how exactly does a CO2 laser work? Anyone knows?
  • weggyweggy Join Date: 2003-06-04 Member: 16998Members
    Those carbons atoms have sharp edges.

    Yeah, i'll just go with that.
  • NecrosisNecrosis The Loquacious Sage Join Date: 2003-08-03 Member: 18828Members, Constellation
    Not to get too technical, it basically involves using CO2 gas to ensure a very efficient turnover. Why CO2? Because its cheap and readily available, for the most part.

    The technical side is that the produced LASER is at a longer wavelength, well into the IR range. Think souped up microwaves. Wood, plastic, etc, absorb this wavelength readily, making it an excellent cutting tool for those materials.

    Also, to use CO2 you also use nitrogen, another cheap gas. Cheap = cost effective, which is very very good when you're playing with expensive toys. It also snuffs out fire, very handy if your laser does something bad (you do NOT want to see a superheated O2 tank folks). Helium's used as well, and again you'll note Helium isn't known for being flammable.



    I would imagine its an even mix between safety, affordability, and sheer cutting power.
  • ZaphodZaphod Join Date: 2003-12-30 Member: 24882Members
    Intensify = more photons = more CO2 atoms = more pumping = more power supplied to gas tank.

    *Amateur* lasers are built by highly qualified engineers mostly. I think you're shooting mighty high.
  • P-KhanP-Khan Join Date: 2003-05-27 Member: 16776Members
    <!--QuoteBegin-Zaphod+Apr 15 2004, 09:11 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (Zaphod @ Apr 15 2004, 09:11 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin--> *Amateur* lasers are built by highly qualified engineers mostly. I think you're shooting mighty high. <!--QuoteEnd--> </td></tr></table><div class='postcolor'> <!--QuoteEEnd-->
    The last idea for a project of mine was mighty high. This is more down to Earth. Literally.

    Plus, it's worth the try. If it doesn't work, I'll try something new,
  • TheWizardTheWizard Join Date: 2002-12-11 Member: 10553Members, Constellation
    /me used a CO2 laser to roast marshmellows once. ^_^
  • MantridMantrid Lockpick Join Date: 2003-12-07 Member: 24109Members
    <!--QuoteBegin-Xyth+Apr 15 2004, 11:00 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (Xyth @ Apr 15 2004, 11:00 AM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin--> If you are really just looking for a cool thing to build for fun or like a science fair, make a railgun or coilgun, very fun, high possibility of electricuting yourself(part of the fun factor), and potentially very powerful. <!--QuoteEnd--> </td></tr></table><div class='postcolor'> <!--QuoteEEnd-->
    What exactly is a coil gun, and how does one go about creating one?

    I'm intrigued...

    And aren't camera flashes just lights that require quite a bit of energy hooked up to a capacitor?
  • TheWizardTheWizard Join Date: 2002-12-11 Member: 10553Members, Constellation
    edited April 2004
    <!--QuoteBegin-tommyd+Apr 15 2004, 01:31 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (tommyd @ Apr 15 2004, 01:31 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin--> if you put your hand in front of a ~1.55um laser that runs at >1mJ/10Hz (non eye safe) you can actually 'feel' the laser pulse even tho u cant see it.  ive done it before, it's fun. <!--QuoteEnd--></td></tr></table><div class='postcolor'><!--QuoteEEnd-->
    Thats true, It is also how some scientists propose we propel spacecraft. As light does provide a measureable amount of force as it bounces off an object.

    1. Build Giant laser on moon
    2. Make a nice SHINY spacecraft
    3. Shoot it with the laser.
    = very fast space travel (eventually)

    Here is a video demonstrating the process (about halfway through)
    <a href='http://www.thevorpal.com/LTI.asx' target='_blank'>Video Demonstration</a>
  • DragonMechDragonMech Join Date: 2003-09-19 Member: 21023Members, Constellation, Reinforced - Shadow
    <!--QuoteBegin-wizard@psu+Apr 15 2004, 06:40 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (wizard@psu @ Apr 15 2004, 06:40 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin--> <!--QuoteBegin-tommyd+Apr 15 2004, 01:31 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (tommyd @ Apr 15 2004, 01:31 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin--> if you put your hand in front of a ~1.55um laser that runs at >1mJ/10Hz (non eye safe) you can actually 'feel' the laser pulse even tho u cant see it.  ive done it before, it's fun. <!--QuoteEnd--></td></tr></table><div class='postcolor'><!--QuoteEEnd-->
    Thats true, It is also how some scientists propose we propel spacecraft. As light does provide a measureable amount of force as it bounces off an object.

    1. Build Giant laser on moon
    2. Make a nice SHINY spacecraft
    3. Shoot it with the laser.
    = very fast space travel (eventually) <!--QuoteEnd--> </td></tr></table><div class='postcolor'> <!--QuoteEEnd-->
    Actually such flight could be sooner than "eventually;" some scientists have already made a light powered flying disk which they can launch to hundreds of feet in the air if I remember correctly.
  • TheWizardTheWizard Join Date: 2002-12-11 Member: 10553Members, Constellation
    <!--QuoteBegin-Dragon_Mech+Apr 15 2004, 07:43 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><b>QUOTE</b> (Dragon_Mech @ Apr 15 2004, 07:43 PM)</td></tr><tr><td id='QUOTE'><!--QuoteEBegin-->
    Actually such flight could be sooner than "eventually;" some scientists have already made a light powered flying disk which they can launch to hundreds of feet in the air if I remember correctly. <!--QuoteEnd--> </td></tr></table><div class='postcolor'> <!--QuoteEEnd-->
    hehe, take a look at the video I added to my previous post as an edit.
  • ZaphodZaphod Join Date: 2003-12-30 Member: 24882Members
    edited April 2004
    Yea, they've made a laser rocket, but they're ridiculously inefficient. Photons do have momentum, so you can shoot it out the back of anything to give it thrust. Obviously you just need a enormous amount.

    Ok, CO2 lasers work exactly as I described before. To make your own laser you need:
    Laser tube: Usually glass tube, probably 0.5m or more to get any decent power, holds the CO2.
    Mirrors: These are expensive and a little harder to come by due to the fact that CO2 lasers emit in the IR range, most mirrors are made for the optical range. You need a fully reflecting mirror and a partially reflecting mirror.
    CO2 pump: Just a sealed tube of CO2 wont work for too long cuz the CO2 will dissociate and you wont have any CO2 left. Best way to do it is to continually pump in and out CO2. Just pump it in one end and exit out the other.
    Excitation Pump: Looks like they're just electrical DC pulse emitters. With the proper scrap, shouldn't be too hard to make.
    Cooling: The tube is going to get hot, you'll need to cool it down. Probably just with flowing water or something.

    Think that's all. It's expensive and extremely time consuming, but do-able...

    EDIT: <a href='http://www.repairfaq.org/sam/laserfaq.htm#faqtoc' target='_blank'>Look what I found</a>
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