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10 Watt Laser

by Mgt3
Tags: laser, watt
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Mgt3
#1
Mar25-09, 10:03 PM
P: 67
Is it in any way possible to build a 10 watt (battery powered) handheld laser?
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bassplayer142
#2
Mar25-09, 11:16 PM
P: 422
a typical 5mw laser will kill batteries pretty quick. You start putting many orders of magnitude more power in the batteries won't work. Also the efficiency of lasers are very bad so there would be tremendous heat.
berkeman
#3
Mar26-09, 01:04 AM
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Quote Quote by Mgt3 View Post
Is it in any way possible to build a 10 watt (battery powered) handheld laser?
Sure. What's the application? What laser safety training have you had?

Mgt3
#4
Mar26-09, 08:14 PM
P: 67
10 Watt Laser

Quote Quote by berkeman View Post
Sure. What's the application? What laser safety training have you had?
I have not had laser safety training (where can you get instructions), but it's obvious that a 10 watt laser would pose eye and skin hazards. My reason for asking is this: I've seen certain green/blue/infrared laser pointers sold between 500 mW - and 1 watt in a flashlight type unit. It might be useful for people interested in material cutting if you could make a similarly compact, portable unit at a higher output.
berkeman
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Mar26-09, 10:15 PM
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Quote Quote by Mgt3 View Post
I have not had laser safety training (where can you get instructions), but it's obvious that a 10 watt laser would pose eye and skin hazards. My reason for asking is this: I've seen certain green/blue/infrared laser pointers sold between 500 mW - and 1 watt in a flashlight type unit. It might be useful for people interested in material cutting if you could make a similarly compact, portable unit at a higher output.
A handheld unit wouldn't be safe at all. Too easy to slip. Power levels like that require enclosed machines with safety interlocks and other measures.

I'm surprised that "laser pointers" are available in the 1W range as well. Could you provide some web pointers? Hard to believe they are made -- the liability is huge.
mgb_phys
#6
Mar26-09, 10:23 PM
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Quote Quote by berkeman View Post
I'm surprised that "laser pointers" are available in the 1W range as well. Could you provide some web pointers? Hard to believe they are made -- the liability is huge.
This is a country where you can buy assault rifles at the mall rememebr.

There are a bunch of 1-2W DPSS, a few are really 500-600mW 532nm that can run at 1W for a few seconds before over-heating. The really nice feature is that most of them are frequency doubled so there is an unknown amount of 1um infrared that you can't see!
berkeman
#7
Mar26-09, 10:25 PM
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Quote Quote by mgb_phys View Post
This is a country where you can buy assault rifles at the mall rememebr.
True enough. But not silencers. (ironic analogy, eh?)
Danger
#8
Mar26-09, 10:44 PM
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Quote Quote by berkeman View Post
True enough. But not silencers. (ironic analogy, eh?)
But they're so easy to make, who needs to buy one? (My favourite achievement was designing one for a rifle that can be turned on and off.)
Mgt3
#9
Mar26-09, 11:22 PM
P: 67
Please excuse my ignorance on the issue, but what kind of danger does a 1-2 watt laser pose?
Danger
#10
Mar26-09, 11:28 PM
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The most obvious one is visual. Anything with even a small percentage of that power can destroy the retinae in your eyes. Skin burns and accidental fires are also possible in that power range.
Mgt3
#11
Mar26-09, 11:41 PM
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Quote Quote by Danger View Post
The most obvious one is visual. Anything with even a small percentage of that power can destroy the retinae in your eyes. Skin burns and accidental fires are also possible in that power range.
I was unaware that 1 watt was enough to damage skin. At what power does a laser become lethal? More importantly, why are these devices which can inflict, at minimum, irreversible damage to a person's eyes so easily available?
Danger
#12
Mar26-09, 11:46 PM
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Quote Quote by Mgt3 View Post
I was unaware that 1 watt was enough to damage skin. At what power does a laser become lethal? More importantly, why are these devices which can inflict, at minimum, irreversible damage to a person's eyes so easily available?
I am totally unfamiliar with the politics involved. You might as well ask why Tasers are illigal here in Canada, yet can be bought at a grocery store in the US. Lethality depends upon both the location and the duration of exposure, so that question is not really answerable.
Mgt3
#13
Mar27-09, 12:01 AM
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Quote Quote by Danger View Post
I am totally unfamiliar with the politics involved. You might as well ask why Tasers are illigal here in Canada, yet can be bought at a grocery store in the US. Lethality depends upon both the location and the duration of exposure, so that question is not really answerable.
So a 5 watt laser probably wouldn't be lethal?
berkeman
#14
Mar27-09, 12:17 AM
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Quote Quote by Mgt3 View Post
So a 5 watt laser probably wouldn't be lethal?
Lethality is not the issue at all. And skin burns really aren't either. Eye/retina damage is primarily the issue. Blindness is no joke. Wouldn't you agree?
Danger
#15
Mar27-09, 12:18 AM
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Again, location and duration. Neither a shot from a .22 nor thirty seconds with an electric drill in your foot will kill you. Either applied to your temple is a different story.

edit: Hi, Berkeman. You sneaked in on me again.
berkeman
#16
Mar27-09, 12:32 AM
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Quote Quote by Danger View Post
Again, location and duration. Neither a shot from a .22 nor thirty seconds with an electric drill in your foot will kill you. Either applied to your temple is a different story.

edit: Hi, Berkeman. You sneaked in on me again.
And you wonder why they call him Danger...

spaceball3000
#17
Mar27-09, 12:44 AM
P: 41
Quote Quote by bassplayer142 View Post
a typical 5mw laser will kill batteries pretty quick. You start putting many orders of magnitude more power in the batteries won't work. Also the efficiency of lasers are very bad so there would be tremendous heat.
How efficient is bad to you?

Modern laser diodes (multi watt) are have greater efficiencies than 50%.

http://www.repairfaq.org/sam/laserdio.htm#diotoc
In fact, high power laser diodes - those outputting WATTs of optical power - are without a doubt the most efficient light emitter - not just lasers - in existence. Some have electrical to optical efficiencies (DC W in to light W out) of greater than 50 percent! In other words, put 2 watts of DC power in and get out 1 W of light. And, research is in progress to improve this to 80 percent or beyond.

http://www.repairfaq.org/sam/laserdio.htm#dioldlb
Consider: Some commercially available high power laser diodes have an overall conversion efficiency - electrical power in to optical power out - of over 50 percent. Current research is attempting to boost this past 80 percent.

My 50 watt laser diode generates 50 watt of light with 2.5v @ 60 amps (150 watts power in.) 150 watts in and 50 watts out in light = 33.3% efficiency. This is with 4-5 year old solid state laser diode tech.

As for the original question, can one build a 10 watt (battery powered) handheld laser, the answer is a simple yes.

I've powered this 50 watt laser with a few pol-li batteries and a proper shunt resistor, I do not recommend this unless you really know what your doing, i.e. know your internal battery resistance, don't go past C rating, etc..

But the rest of the energy would be in the form of heat, so it will get hot fast, i.e. use proper heatsink, and just don't run it more than x seconds at a time.

FYI, I have proper eye wear (808nm), and I actually stopped using them, as I'm not present in the room, i.e. I use a remote camera to observe. >50mw lasers can get very dangerous, even with 1 watt diode reflecting off dull metal can hit your eye to blind you.
spaceball3000
#18
Mar27-09, 12:50 AM
P: 41
Quote Quote by Mgt3 View Post
Is it in any way possible to build a 10 watt (battery powered) handheld laser?
Yes you can, see my previous post.

BTW please if you do an laser project, please Google "SAM FAQ laser guide" and read all the safety parts. And at Minimum buy (ebay) laser eye protection wear that matches your laser diode range.


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