On lasers...

[Evil Sadistic Bastard]

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 I want one!

It would match my skin colour...

[Enlightenment]

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.

There are operational FELs installed in a fair number of university research labs and similiar places. They're a proven technology up into the kilowatt class if not higher.

Incidentally, DVDs use near IR lasers, not blue. Blue laser diodes were developed at about the same time as the DVD spec was finalized but there is no connection between DVD and blue lasers. Like CDs, DVDs user near-IR lasers; DVD lasers have a shorter wavelength than CD lasers but they're still inside the IR range.

[ClaysGhost]

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.

They're not obsolete; we use one as an accurate frequency standard. A coherent lightsource in a particular wave-band never becomes obsolete. Similarly, X-ray lasers will not make optical lasers obsolete - I mean, who's going to make X-ray laser pointers?

MASERS occur in space naturally; they tend to turn up around large stars, where clouds of gas get excited by photons from the star.

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.

They're not theoretical. They're very useful. For examples, see:

http://sbfel3.ucsb.edu/www/vl_fel.html

Free-electron lasers can indeed be tuned, which is nice. Essentially, a relativistic electron beam is passed through a corrugated magnetic field. The electron beam is made to "wiggle" by this field, and since the electrons wiggle in step and in time the light emitted (any accelerating charge will emit light) is coherent. Proponents allege that a free-electron X-ray laser is possible, which would certainly be more desirable than setting off a nuke every time you needed an X-ray laser pulse.[/url]

[beyond hope]

ooops...

[The Dark]

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!

Why would green work better than blue? IIRC, it's related to wavelength, and if you'll recall ROY G BIV, the further towards blue/violet you go, the better the data storage capacity. Green would be better than red, but inferior to blue.

[beyond hope]

I just found it odd that it was easier to make a blue-wavelength beam than a green one, and that violet-wavelength beams would be a pratical reality first. Evidently that's changed since I last read anything on the subject *curses and remembers to do research before I post.*

[GrandMasterTerwynn]

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.

Answers:

A) You take some medium that emits electromagnetic radiation when hit with energy. It could be a ruby crystal, the gallium arsenide junction of a diode, a cloud of hydrogen flouride, or even a hunk of steel. You make it so the ends are capped with some other medium that reflects the photons you want. The photons bounce back and forth, striking other atoms in the lasing medium and producing even more photons. Eventually you have enough photons flying back and forth that some make it out of the end of your lasing medium (Called a 'cavity'.) And voila, you have a laser.

B) How much power do you want to get out? Your typical laser is very, very inefficient. A typical value for laser efficiency would be about 1 - 2% (CO2 lasers have an efficiency of 5% to 20% and some semiconductor lasers have 10% efficiency) This means that if you want, say a 10 MW laser that can boil bits off comets, you'd need a 1 GW power supply.

C) There are two principle considerations to the size of a laser.
1 - It's power supply. Remember that lasers are very inefficient users of power. This leads us to:
2 - The waste heat generated by the laser. All that energy the laser is wasting has to end up somewhere doesn't it?

D) Non-combat applications of lasers include. LASIK and RK surgeries. These surgeries use lasers to vaporize bits of the cornea, effectively reshaping it. Lasers can also be used to zap cavities and whiten teeth. Also they are used in dermabrasion. And they are used in CD players and DVD players, and in laser pointers.

[Sir Sirius]

Question.
I remember reading about a laser that was powered by the explosion of a nuclear bomb. Can't remember where though. Just wondering is this possible or was it just fiction? If it is possible how powerful could such a laser be (powered by a kiloton range nuke)?

[Darth Wong]

Question.
I remember reading about a laser that was powered by the explosion of a nuclear bomb. Can't remember where though. Just wondering is this possible or was it just fiction?

I seem to recall someone floating the idea of some kind of one-shot X-ray cannon.

Or, you could simply refer to Transformers, and Megatron's FUSION CANNON!

[Sindai]

Question.
I remember reading about a laser that was powered by the explosion of a nuclear bomb. Can't remember where though. Just wondering is this possible or was it just fiction? If it is possible how powerful could such a laser be (powered by a kiloton range nuke)?

They use these in the fairly obscure Starfire SF universe. I don't really know how they're supposed to work; it seems to be something like: detonate a nuke, then shove all of the resulting X-ray radiation towards the enemy in a concentrated beam. (That's the part I can't for the life of me remember the technobabble for.)

Naturally, the "detonating a nuke" part means that they're only used as mines instead of shipboard weapons.

[Enlightenment]

They use these in the fairly obscure Starfire SF universe. I don't really know how they're supposed to work; it seems to be something like: detonate a nuke, then shove all of the resulting X-ray radiation towards the enemy in a concentrated beam. (That's the part I can't for the life of me remember the technobabble for.)

It's not technobabble. Nuke-pumped x-ray lasers have the backing of real-life physics and real-world testing. They're real and they work.

[GrandMasterTerwynn]

Question.
I remember reading about a laser that was powered by the explosion of a nuclear bomb. Can't remember where though. Just wondering is this possible or was it just fiction? If it is possible how powerful could such a laser be (powered by a kiloton range nuke)?

This is the kind of laser where you' use a hunk of metal as the lasing mechanism. You whack it with a nuclear explosion and it produces X-rays as it is turned to vapor. This type of laser would be really powerful, but you'd probably want to put it on some sort of missile.

[Slartibartfast]

Question.
I remember reading about a laser that was powered by the explosion of a nuclear bomb. Can't remember where though. Just wondering is this possible or was it just fiction?

I seem to recall someone floating the idea of some kind of one-shot X-ray cannon.

Or, you could simply refer to Transformers, and Megatron's FUSION CANNON!

Yeah I posted something like that on one of those "best realistic space weapon" or whatever. Basically a nuclear missile with a x-laser cannon that is fired from a ship, and after a certain distance (not sure if it should be as soon as it clears from the firing ship, or after closing on the target somewhat) it blows up and a x-ray laser is fired.

I read it somewhere, I think it's one of my RPG books.