On lasers...

[Evil Sadistic Bastard]

Okay, just to show that I am not completely boneheaded, I KNOW a laser is a beam of coherent light, I know it seems to be the fundamental energy weapon of most sci-fi series

Problem is, I need to know:

How do you generate a laser? (I've heard of multiple ways to do it, like free-electrons, gas, or whatever)

How much power would a laser require?

Are there any space limitations associated with building a laser (i.e does it have a minimum size etc.)

What are the non-combat applications of lasers?

Feel free to add any information you deem fit to share.

Thanks.

[guyver]

What are the non-combat applications of lasers?

A non combat use is for eye surgey. I have worn glasses all my life, since I was 10. I am going to have laser surgey done on my eyes. This will than give me almost perfect vision. It is not a cheap thing to have done, it is going to run me 2500 dollars US.

[Evil Sadistic Bastard]

A non combat use is for eye surgey. I have worn glasses all my life, since I was 10. I am going to have laser surgey done on my eyes. This will than give me almost perfect vision. It is not a cheap thing to have done, it is going to run me 2500 dollars US.

Oh yes, that.

I've heard good and bad things about it... Apparently if done right it CAN correct bad vision. But if not done correctly it could blind you. That's why laser surgery in my country is done one eye at a time.

Now I wonder... How does the laser do it?

[guyver]

I've heard good and bad things about it... Apparently if done right it CAN correct bad vision. But if not done correctly it could blind you. That's why laser surgery in my country is done one eye at a time.

Now I wonder... How does the laser do it?

It does it by flating the back part of your eye. So the doctor tells me. And yes I am only doing one eye at a time. The doctor would only allow me to do it that way.

[Darth Wong]

How do you generate a laser? (I've heard of multiple ways to do it, like free-electrons, gas, or whatever)

Make light, bounce it around.

How much power would a laser require?

Depends on how powerful you want the laser to be.

Are there any space limitations associated with building a laser (i.e does it have a minimum size etc.)

Every compact disc player has a laser in it. Laser pointers are also real lasers; that's not just a name. You can make lasers very very small.

What are the non-combat applications of lasers?

See above.

[TrailerParkJawa]

Lasers are used in industrial settings to cut things like steel.
There is a shop here in my area that has machine that will custom cut
things for you.

I saw it on tv, some guy had letters cut into the side of computer case. It was pretty cool, and if I recall correctly it was like 100 bucks or so.

[TrailerParkJawa]

Oh and just to add, lasers can be used to transmit data. That is what my last company did. They build optical networking devices.

[Admiral Valdemar]

Lasers are diverse in use and nature of working in the world. You can use them from everything from targetting to reading data to cutting or colouring (laser printer uses toner in a magical way) and so on.

It is just very good coherent light.

[kojikun]

Since noone (even mike ;P) has given a good answer for how to generate lasers, here goes:

Take a medium, such as solid ruby or gaseous helium-neon mix, get it to give off light by energizing it (in ruby lasers i believe they use flash tubes, in HeNe lasers I believe its done like in a standard neon sign is used). When electrons deenergize they give off light. The key is to get the electrons to deenergize in synch with one another so the light is coherent and more powerful. Lasers also use mirrors on either end to bounce light back into the medium, so that coherency builds. One of the mirrors has to allow light to pass through it, but it only does so at a certain intensity (its silvered). Some of the light is bounced back into the medium, some is let through. You thusly have a laser. Tho its much more complicated then this.

[Asst. Asst. Lt. Cmdr. Smi]

How can you use lasers to correct your vision? Whenever I point a laser in my eyes, my eyes start to hurt. (/moron)

I have another question: Can a laser go out of focus over time, like ordinary light does, but slower?

[kojikun]

Look up Lasik.

Lasers do spread out, eventually, but over MUCH greater distance then normal light. If I'm not mistaken, a laser point pointed at the moon would project a spot a meter wide or something ridiculously small like that.

[corporial]

Lasers correct vision by changing the shape of the cornea. Changing the shape just does the same thing that eye glasses do, it changes the angle of refraction.

[Sea Skimmer]

Beyond eye work and CD's, Lasers can also be used for communications, some factories use them for guiding Robotic systems, Laser range finders and pointers also get used for survey work. The Surface of Mars was recently mapped by a satellite with such a laser. It took millions of measurements which once combine produced a map more accurate then older radar maps.

[SWPIGWANG]

lasers is a useful concept to annoy warsies in conjunction with deflectors.

[Vympel]

Laser rangefinders are used by main battle tanks, aircraft, helicopters, and other military vehicles to determine the range of a target for accurate firing. They are also used as a guidance medium- e.g. Hellfire and Vikhr-M missiles.

I know it's non-combat application- but who cares.

[beyond hope]

They're fairly impractal as a weapons system for the time being: the problem is thermal efficiency, the best *theoretical* design (the free-electron laser) only emits at best 20% of the energy put into it as a beam. The other 80% is waste heat... with any laser design, heat is a big problem. It also takes a surprising (well, to me) amount of energy to kill someone with one: what you're doing essentially is vaporizing the equivalent quantity of water, meaning that a laser powerful enough to do it is the size of a large MG or even a small cannon. Not very practical as an infantry weapon when you consider the power has to come from somewhere, too.

What I was surprised by is that the next wavelength they've successfully got to work in the lab for small lasers like laser pointers or CDs is violet wavelength. Green is apparently a big problem due to lack of a suitable lasing medium for it. It'll be cool to see whether it allows even greater data storage like DVDs with their blue-wavelength beam did over CDs.

[Slartibartfast]

Okay, just to show that I am not completely boneheaded, I KNOW a laser is a beam of coherent light, I know it seems to be the fundamental energy weapon of most sci-fi series

Problem is, I need to know:

How do you generate a laser? (I've heard of multiple ways to do it, like free-electrons, gas, or whatever)

I'm no genius but the general idea is that normal light doesn't travel in a straight line (or not all frequencies, whatever) and diffuses as it goes. Then you have something like a Ruby, which somehow is the equivalent of lots of mirrors reflecting into the inside, and one of the sides allows rays to get out. The result is that all the "threads" of light eventually bounce and become aligned as they find this magical one-way exit spot.

I think the trick is to polish all sides of the gem except one.

Then you can do it by exciting gases. I think these are called pulse lasers because you actually generate it hundreds of times per second, unlike the first method which is a single continuous beam. You gain coherence by using actual mirrors instead of the walls of the ruby.

There are a few webpages in the 'net that explain it better.

How much power would a laser require?

For what? Laser pointers use a single tiny battery.

Are there any space limitations associated with building a laser (i.e does it have a minimum size etc.)

Again, see laser pointers. Or the laser header in a CD player.

What are the non-combat applications of lasers?

Laser surgery (specially eye-surgery), again, laser pointers, laser sights on pistols (well kinda combat-app but not quite), laser rangefinders, laser detectors for speeding cars, laser discs (including CD, DVD, and magneto-optical), dance club special effects, laser communications, etc. Also to cut metals and stuff.

Oh yeah and never point even the weakest laser (ie, a laser pointer) to your eye. It causes your retina to "dismembrane" or whatever it's called in english.

[Drewcifer]

Check out http://www.howstuffworks.com/laser.htm

Table of Contents:
› Introduction to How Lasers Work
› The Basics of an Atom
› The Laser/Atom Connection
› Types of Lasers
› Laser Classifications
› Lots More Information!

[beyond hope]

Oh yeah, types...

Masers are the ancestors of modern laser technology. they're the same exact idea, using lower-wavelength microwave radiation. lasers have largely rendered them obsolete, although you'll still find them in some industrial applications.

solid-state lasers are the most common form: they use solid crystals (rubidium being a good example) as their lasing medium.

dye lasers use a constantly-circulating fluid as their lasing medium

gas-dynamic lasers use a constantly-circulating flow of gas as their lasing medium, and are somewhat like a turbine in design. the lasing mediums used in dye and gas lasers tend to have the problems of being either poisonous or flammable, and fires in gas laser labs are a chronic problem. it's easier to get a liquid or gas to lase, however, since the atoms are already starting at a higher energy level.

excimer lasers are a subcategory of gas lasers, using compounds called excimers which create a rapid series of pulses rather than a steady beam

X-ray lasers are one shot weapons, investigated to serve as part of SDI. essentially they're a nuclear warhead covered in emitters: the explosion provides the X-rays. Earth's atmosphere is fairly opaque to X-rays, so they're most useful in space.

free-electron lasers use a series of electromagnets to generate a coherent beam of light, something like a mass-driver or a particle cannon. To the best of my knowledge they're still totally theoretical. one other plus with this sort of laser: unlike lasers with a physical lasing medium where the medium determines the wavelength, you should be able to "tune" a free-electron laser to whatever wavelength you desire.

lastly, gamma-ray laser weapons would theoretically be possible as well, if we could figure out how to make a coherent beam of gamma rays.

P.S. forgive the double post[/b]

[Vympel]

Oh yeah, types...

Masers are the ancestors of modern laser technology. they're the same exact idea, using lower-wavelength microwave radiation. lasers have largely rendered them obsolete, although you'll still find them in some industrial applications.

solid-state lasers are the most common form: they use solid crystals (rubidium being a good example) as their lasing medium.

dye lasers use a constantly-circulating fluid as their lasing medium

gas-dynamic lasers use a constantly-circulating flow of gas as their lasing medium, and are somewhat like a turbine in design. the lasing mediums used in dye and gas lasers tend to have the problems of being either poisonous or flammable, and fires in gas laser labs are a chronic problem. it's easier to get a liquid or gas to lase, however, since the atoms are already starting at a higher energy level.

excimer lasers are a subcategory of gas lasers, using compounds called excimers which create a rapid series of pulses rather than a steady beam

X-ray lasers are one shot weapons, investigated to serve as part of SDI. essentially they're a nuclear warhead covered in emitters: the explosion provides the X-rays. Earth's atmosphere is fairly opaque to X-rays, so they're most useful in space.

free-electron lasers use a series of electromagnets to generate a coherent beam of light, something like a mass-driver or a particle cannon. To the best of my knowledge they're still totally theoretical. one other plus with this sort of laser: unlike lasers with a physical lasing medium where the medium determines the wavelength, you should be able to "tune" a free-electron laser to whatever wavelength you desire.

lastly, gamma-ray laser weapons would theoretically be possible as well, if we could figure out how to make a coherent beam of gamma rays.

P.S. forgive the double post[/b]

You left out turbolasers.

[beyond hope]

I left off the sort that magically don't work on Star Trek shields, too...

[Vympel]

I left off the sort that magically don't work on Star Trek shields, too...

Ah endless fun.

Speaking of lasers- did Okona ever appear in ST again?

[Durandal]

Lasers work because bosons don't obey Paulie Exclusion. The photons that transmit light can exist in the same quantum state all at once. So, when you make a bunch of photons exist at the same energy level, you get a laser. Most laser pointers pass light through a gas in such a way that the gas will emit photons of similar quantum states, I think. I'm pretty sure they use a noble gas, like xeon.

[Evil Sadistic Bastard]

Well, thanks to everyone who contributed. I have learned marvellous much from this.

[aerius]

What I was surprised by is that the next wavelength they've successfully got to work in the lab for small lasers like laser pointers or CDs is violet wavelength. Green is apparently a big problem due to lack of a suitable lasing medium for it. It'll be cool to see whether it allows even greater data storage like DVDs with their blue-wavelength beam did over CDs.

It's kinda strange that they haven't find a proper lasing medium for green lasers to be used in data storage. We've already had green laser pointers out on the market for over a year now and other than high cost there's no real issue with them. Mmmm Green laser pointer, I want one!