Laser mythology.....

[rog8811]

You can't tell me no one posted "lightsaber" from Star Wars yet. I'm amazed.

There is grade A material!

A self terminating light weapon aka "LASER",

Ahem.... watch this space

"Snirk" rog8811

 

[RA_pierce]

That's a funny new category: laser uses that were mythical at the time the movie was made, but have now come true. Perhaps we can find some old movies where someone started a campfire (or something like that) using a laser pointer.

I can do that!
2W of 808.

If any of you have seen "Get Smart"
There is a scene where this guy takes one of the tuning keys out of his violin and it's actually a red laser that can melt through metal.

And in Oceans Eleven... the security lasers don't even reflect off the shiny floor.

 

[Elektrotechniker]

I don't know if you watch any greek tv programs but greek basketball games are now f*cked up. There are a lot of fans carrying greenies most of which are 5mW and point at basketball players.

 

[bschott]

I, too, used to believe in the wole never-diverging, dot-would-still-be-the-same-size-even-a-mile-away thing. The first time some friends and I were screwing around with lasers at long distances and I saw, first hand, significant beam divergence, I thought my buddy had a cheap laser.

I learned about beam divergence when I was in grade school and a science text book described the Laser Ranging Retroreflector experiment on the moon. Before that, I also believed a laser beam always stayed the same diameter and just lost power the further away the lased object was.

Edit: Ah, I found the website after 10 minutes of searching!
http://www.lpi.usra.edu/lunar/missions/apollo/apollo_11/experiments/lrr/

Excerpt:
"Laser beams are used because they remain tightly focused for large distances. Nevertheless, there is enough dispersion of the beam that it is about 7 kilometers in diameter when it reaches the Moon and 20 kilometers in diameter when it returns to Earth. Because of this very weak signal, observations are made for several hours at a time. By averaging the signal for this period, the distance to the Moon can be measured to an accuracy of about 3 centimeters (the average distance from the Earth to the Moon is about 385,000 kilometers)."

 

[ChukiDori]

You can't tell me no one posted "lightsaber" from Star Wars yet. I'm amazed.

There is grade A material!

A self terminating light weapon aka "LASER", with phenomenal power that collapses into a pocket device and can deflect incoming objects. Available in Red, Blue or Green.

Hollywood at its finest!

At least in "Real Genius" the laser continues through objects.

Well..A light saber is obviously Plasma, as it would have all the necessary criteria ^_^. Super hot, Self terminating, Contained via magnetic fields..which could repel other directed energy plasma weapons (Blasters) which are also highly electricaly charged, or more likely just dissipate them and other "light sabers" them selves.


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Oh and the biggest myth of all I cant believe no one has said it yet. That laser beams actually make a sound. Aside from the crackling of the burning surface and the electronic equipment in the laser it self..theres no cool Pew Pew Pew sound .

Or do true "High power" lasers really make sounds? (Not mechanical sounds, sounds from the beam discharge)

 

[Jaseth]

Yes RA_pierce, there is also the scene in Get Smart where the red lasers cut up his suit whenever he leans into them by accident. As far as I remember the beams aren't even broken but slice apart his suit as if they were long glow wires or something, solid death rays :crackup:

I used to believe that all sniper rifles had lasers which could send a 2mm wide dot on any target at any distance.
I also thought that James Bond's laser watch in Goldeneye was real.. it was so cool, and in the Nintendo64 game too

 

[HIMNL9]

You mean as in the resident evil film, where not only a laser beam cut dresses and slice a shoe part just passing, but then convert itself in a grid of beams and slice a body in cubes ? ..... LOL, i also want one of those beams that self-convert themselves, then

And about lightsabers, ok, THEORICALLY is possible to use a high power laser for make a plasma bar, and confine it inside a magnetic field ..... but you now just have to produce a magnetic confinement field sustained from one side only, with the shape of a tube, a cap at the end on a fixed lenght, and that is strong enough to confine plasma inside it ..... but also that have all the magnetic lines self-confined inside itself, if you don't want to attract on your saber all the pieces of metal of all your house, when you turn it on (if you know the magnetic energy needed for constrain plasma in a closed magnetic tube, you know what i mean, LOL)

 

[ChukiDori]

You mean as in the resident evil film, where not only a laser beam cut dresses and slice a shoe part just passing, but then convert itself in a grid of beams and slice a body in cubes ? ..... LOL, i also want one of those beams that self-convert themselves, then

And about lightsabers, ok, THEORICALLY is possible to use a high power laser for make a plasma bar, and confine it inside a magnetic field ..... but you now just have to produce a magnetic confinement field sustained from one side only, with the shape of a tube, a cap at the end on a fixed lenght, and that is strong enough to confine plasma inside it ..... but also that have all the magnetic lines self-confined inside itself, if you don't want to attract on your saber all the pieces of metal of all your house, when you turn it on (if you know the magnetic energy needed for constrain plasma in a closed magnetic tube, you know what i mean, LOL)

Keep In mind our own knowledge of physics is very limited...The whole technological state of starwars universe was thousands of years beyond us...

Its possible it may even BE a laser and confined due to some new physical law we have yet to discover or manipulate.

Now a Blaster is possible...The terminator mythology expands more on directed plasma bolts in GREAT detail. Even giving rather believable data sheets and different phases of Skynets Plasma development and weapon phases.

It could theoreticaly be possible to channel a bolt of plasma just like a Gauss gun or Rail gun would propel a solid projectile...If launched fast enough (Hyper sonic speeds, speed is key) The plasma could reach its target before it lost cohesion and maintain its "magnetic charge" for a few micro seconds.

Still. This is the biggest "Myth". The Myth that directed energy weapons will become so prevelent they replace projectile weapons.

I dont care how easy it becomes..It will always be easier to make a bullet, and a bullet has more practical anti personnel effects than any energy weapon will..Why would you need a laser or a plasma weapon? Short of space warfare and anti -tank and point defense? To kill someone? a bullet will kill someone. To pierce body armor? A bullet can pierce body armor...and it will ALWAYS be more feasible than a blaster of some sort.

 

[HIMNL9]

^ Also, consider one thing: so-called "laser guns" is very difficult that anyone reach to made a laser gun that can "pass" a body, like in films.

A body is, basically, a bag of water (ok, more or less, but the thermical coefficent is almost the same) ..... want to shot a hole in it ? ..... you need to pump enough energy for vaporize all the deepth before the movement and gravity put other liquids and materials in the beam place ..... say, 1 uS ? ..... ok, for the medium depth of the body, can need 20 KW or more, for an 1mm diameter hole ..... but in 1 uS, that means a continuous rate of 20 TW !

Speaking following the laws of phisics, the better way for made a working laser weapon, perhaps the way of building a heat pump ..... yes, not joking, the laser, repeated pulsed at 10/15 mS pulses, large beams, a pair of cm, at some KW, that "pump" in the body more heat of that what the body can dissipate, "cooking" literally the opponent from the inside ..... for sure, no "drill and cut" action Hollywood style

 

[ChukiDori]

I think if a laser can destroy a missile it can destroy a human? Maybe im wrong.

Ive heard of 30 watt lasers causing severe tissue damage at close range also...so why couldnt a KW laser fuck someone up with a short pulse?

Thats more directed energy than whats in a bullett by far...And from my readings recently a .45 round converting all its energy to thermal energy at impact would = like 350 degrees celsius. so a CW laser at 1 KW should be able to fuck a person up.

Id say its damaging...for sure...but still not AS practical as a bullet would be ^_^

 

[HIMNL9]

^ Cause it's not just matter of pulsed power, but overall of reflection/absorption range, transferred energy and dissipation.

Sorry, but isn't enough shoot a 2Kw beam on a body, for pass it ..... i worked a pair of years with a CNC cutting machine ..... it was 2KW IR CO2 "U tube" laser, and i can cut til 25mm of 789 type special steel at about 10cm/second (a bit less with complex cutting geometry) ..... but this using special lenses that focus the beam at 1/10 of mm in the region of the cut.

Usually, you can't produce this type of beam at distance, but we can suppose, for the discussion, that you can ..... ok, now you shoot the laser on someone ..... first, the person that you target is not antireflection-opacized-surface-treatened like the steel plates i was working , so part of the powre become reflected from the skin, as initial (at least til you don't drive on it enough power to carbonize the hit point ) ..... then the inside of the body is basically comparable to a water container, as thermical gradient of heat diffusion, (also a bit more, considering the forced blood circulation ), so it dissipate a lot of heat in the whole body, in the vaporization process ..... other more energy to shoot in ..... then, for the nature of the blood and meat and for the gravity effect itself (not mentioning blood pressure, and not mentioning also the fact that the vaporized material, forming a cloud in front of the hit point, still disperse other energy ), where you vaporize, other material and blood take the place of the one vaporized, requiring other power, and so on.

And, more important thing, your opponent is not a piece of metal, that quietly and indifferently sit in place while you're shooting it, he move, changing the hit point and the angles of your weapon-target thermodinamic system

And last, we're still talking about a beam of 0,1mm of diameter, that isn't really effective for damage someone really hard (if you don't hit brain, heart or some really delicate vital organ, is difficult that you can kill someone also passing him part to part with an 0,1mm diameter nail )

Usually in the film the beams are around 2 cm diameter, do you want to calculate how much energy you have to pump in the beam, for obtain the effect that you want ? ..... prepare a large paper, anyway, cause i guess you end with a considerable number of zeroes

About the lasers destroying missiles and so on, they destroy them makin them hot enough that the inside explosive self-detonate, not disintegrating them ..... THEL is actually the more (non-secret) efficent one .....

http://www.youtube.com/watch?v=LThD0FMvTFU
http://www.youtube.com/watch?v=cCBwLJjzDJQ

and as you can see in the videos, it still have to hit them for some seconds, usually 3 to 6, for blow them

BTW, this is a test of an 1KW unfocused 10mm diameter beam (IR, from a cutting CO2 laser), through a plexiglass block (and NOT through metal, as the poster of the vidro says LOL, this guy knows a damn nothing about cutting lasers ) ..... plexiglass is always used for check the realignment of those types of lasers when they need maintenance, cause a bad-aligned cavity melt an irregular shaped disc, while a well aligned one melt nice round regular spots also with short pulses, and is more easy to cut and punch of a human body

http://www.youtube.com/watch?v=GQRokhfiYQE

 

[Schrecken_Licht]

There's a really good book out there for anyone interested in laser weapons and what they might be capable of. Check out "Beam Weapons" by Jeff Hecht. It's an older book, dating from the 80's, I think, but much of the info is still relevant. In the book, the author calculates the amount of laser energy required to instantly (in one second) burn a hole (sorry I don't recall the size of the hole, I'd have to go look) clear thru a human body (somewhere in the torso), which he estimates at 50,000 joules (or roughly equivalent to 50KW per second, I think).

That's well within the range, power-wise, of many industrial CO2 systems. However, you would have to have the right sort of optics (the sort of adaptive optics used by the Airborne Laser would work, but not the sort of lenses you'd have around a laser machine shop) to get the focused beam to the target, depending on the distance the beam would need to travel.

One effect pulsed laser weapons might have on human targets is that the water in flesh is super-heated by the laser pulses and literally explodes like a potato in a microwave. This has been seen to happen on a very small scale (and relatively weak laser powers) in eye injuries where the retina is damaged by blood vessels bursting. You wouldn't have to just sit there and try to burn a hole thru someone with a CW laser (which of course they'd just keep moving out of the way, like what happened with a tick I tried to kill with my Blu-ray laser - I had to follow its movements with the beam to eventually destroy it), a rapidly pulsed laser could rapidly vaporize and explode flesh.

Of course, if you have enough CW power, something like the Advanced Tactical Laser could simply torch and kill someone like an ordinary flame-thrower.

As for bullets vs directed energy weapons, there are a couple of reasons, based on what I have read, as to why the continued military interest in DEWs.

Unlike firearms, a laser weapon will never run out of "ammo" as long as its power supply is getting electricity. This of course applies to vehicle-mounted laser weapons, as, since we can barely come up with enough stored electricity to power an all-electric passenger car any distance (and even then the price is prohibitive), it will be a very long time before there's any sort of battery or truly portable power source that could adequately supply a hand-held laser gun. As long as you have power to the laser, it can shoot indefinitely + there's no ammo to store, carry and handle.

Also, with kinetic weapons of any kind, you have problems like windage and gravitational drag on the bullet. This can be accounted for, but a laser is far more accurate - no matter the distance, or which way the wind is blowing, or how fast the target it moving - if you can target it you can hit it. There's also much less ability of the target to take evasive action.

Then there's the whole psychological thing - if you hear gunfire (and of course you've not been hit) you can duck or otherwise try to avoid being hit. But with a laser as an antipersonnel weapon, you'd hear and see nothing - the guy fighting next to you would just fall over dead or burst into flames. If your buddy gets shot dead, you'd have some rough idea as to where the gunfire came from, and then you'd duck and run. With a laser, it's far less likely that you would have that second chance as you might not even know what killed your buddy or where it might have come from.

Of all of the research I have done on laser weapons development, these seem to be some of the main reasons why the military is pursuing directed energy weapons. There will still be places for bullets and bombs in the future, but also for lasers.

 

[HIMNL9]

There's a really good book out there for anyone interested in laser weapons and what they might be capable of. Check out "Beam Weapons" by Jeff Hecht. It's an older book, dating from the 80's, I think, but much of the info is still relevant. In the book, the author calculates the amount of laser energy required to instantly (in one second) burn a hole (sorry I don't recall the size of the hole, I'd have to go look) clear thru a human body (somewhere in the torso), which he estimates at 50,000 joules (or roughly equivalent to 50KW per second, I think).

When i was working with it, our 2KW/S cutting unit was a box 3 meters high, 1,80 meters long, and 1 meter large ..... and i mean, only the emission cavity and the related power supply, excluding vacuum unit, pumps, valves, CO2 cans, pipes, and all the rest.

Just wondering how much "portable" can look a 50KW/S unit

 

[Benm]

The use of lasers as military weapons isn't that mythical anymore... as shown in the videos above.

The sole advantage is that it works at the speed of light, something no bullet or missile can even remotely approach. Shooting down an incoming projectile with a bullet is very difficult, and if you miss, you have to start all over again... a laser beam can be adjusted in the process to keep track of the target. Makes a great defensive system.

Lasers as offensive weapons are a thing of myth, and probably will remain so for a long time. Bullets and bombs will likely be more cost effective regardless of technological advances in lasers. Surely you could shoot and kill a person with that isrealy missile tracker, but i think the power bill will be a lot higher than the price of an equally effective bullet.

Also, the effectiveness of that laser interceptor relies on an enemy shooting mortars. I'm sure it would be possible to give the projectiles a (retro)reflective coating rendering them immune to interception. It works because the enemy there isn't likely to develop that.

 

[HIMNL9]

The collimating system uses a combination of radar and light tracker ..... the high speed radar (basically the same type of the CISW GoalKeeper) engage the target, aim the laser, and keep it pointed, where the optical tracker keep the beam focused, but the tracking is anyway a combination ..... a high reflective coating can improve the resistance of the bullet a lot, but must be a shiny-mirror coating type ..... and, anyway, must be optimized for IR wavelenght, maybe a multilayer coating trimmed on the same wavelenght ..... but at this point, your bullet become more expensive of all the rest of the weapons together

 

[Greendream]

I didn't think laser light was visible unless there was a fog or some particles in the air for the beam to reflect on (I didn't realize higher power lasers will show a beam without fog).

I have to admit that I was guilty of thinking this too. To a certain degree, I think it's right though, since you cant see lasers in a vacuum, can you?