# Supercapacitors for the ultimate portable laser gun/burner?



## mailint (Sep 29, 2007)

At https://www.candlepowerforums.com/posts/2167020 I'm writing about a supercapacitor already on the market that can delivery 100A at about 3V in 1-2grams and 28x17x1mm dimensions.

Now take 10 of these and you have 1000A.

Wouldn't this be sufficient to emit laser pulses of 1000 WATT with the power of a thing (the supercapacitor) as big as a 9V battery?


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## Fallingwater (Sep 29, 2007)

I believe you would need a hell of a large heat sink (not to mention a ridiculously expensive laser emitter) to create a laser that draws 1000 amps.


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## mailint (Sep 30, 2007)

Fallingwater said:


> I believe you would need a hell of a large heat sink (not to mention a ridiculously expensive laser emitter) to create a laser that draws 1000 amps.


 
heat sink for a laser pulse? well, it depends on how long is the laser pulse...


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## lazerlover (Oct 1, 2007)

How would using a capacitator work in order to generate a pulsed beam for a split second? I mean if you wanted to get a 1W green beam for a split second, would the capacitator just need to "charge" enough to satisfy the operating voltages/current of perhaps a 5W 808nm laser diode? If so, that should be quite simple to build DIY


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## npkeith (Oct 1, 2007)

Has anyone very built one of these: (from the Information Unlimited website)

*A Futuristic Concept! *
*Laser Ray Gun*

[SIZE=+1]*Laser Gun - *[/SIZE]A prelude to a weapon of the future - the technology is here! *Now Available -* hand held, battery operated, 500 joules of pulse energy produce an intense burst of light capable of burning holes in most materials. 
*This is a dangerous Class IV laser project and requires initial purchase of plans including our Hazardous Equipment Affidavit that must be signed before purchase of the actual system.*

Input Voltage: 12VDC @ 1.5AMPS, 20-30sec. Charge Time
Rod: 3X1/4" Nd:GLASS With Integral Mirrors
Output: 3 Joules @ 1.06 Microns Infra Red
Storage Capacity: 270 Micro farads @ 2 KV
Flash lamp Energy @ 1000 Volts: 135 Joules, @1500 Volts: 300 Joules
Single Colimnatting Lens
120 to 150 Shots From Internal AA Batteries
Certified Class 4 Laser Product
*The Purchase of Plans Is Creditable Actual Hardware Purchase*

You can get the plans for 20 bucks, or the complete laser (minus the ruby laser rod) for just under $1800 (!)

Given that the first lasers every made were a flashlamp and a ruby rod, and power was measured in "Gillettes" (the number of razor blades it could burn through...), the basic concept is sound.

Pretty scary concept, although I doubt the effective range is beyond a few feet...


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## lazerlover (Oct 2, 2007)

I've seen that before, I'm wondering if DPSS technology could be used in place.


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## npkeith (Oct 2, 2007)

Interesting idea - you would only need the the KTP crystal too - the Nd:YVO4 crystal is only there to take 808nm IR from the diode down to 1064nm, and then the KTP halves that to green 532nm. The rod puts out IR at 1.06 microns, or 1060nm - only 4nm off. I wonder if the KTP would respond to that? 

A blindingly bright green flash. Hmm... 3 joules. How do you calculate the wattage from that - watt = joule/second. How long is the pulse from a flash lamp laser? Wikipedia says that a typical flash is a microsecond or a millionth of a second. So:

3/.000001=3,000,000W 

Say what? 3 megawatts? That can't be right. Someone fix my math. Maybe my assumption about the duration of the flash is wrong. 

Help? Anyone?


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## mailint (Oct 2, 2007)

I'm try to follow that "laser gun" from more than 1 year but I still not read of anyone who have it.

Anyway the combination battery+supercapacitor would be great!


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## RDZombie (Oct 2, 2007)

Information unlimited had that laser gun as "comming soon" for years, im surprised they finally finished it. hell i bought one of there first red pointers maybe 10 years ago. they had that gun in the catalog that came free with it LOL. question tho, its ND:glass, not ND:yag like most KTP lasers. ND:YAG is 1064nm while glass is 1060nm. Would probably still work but not as efficient?


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## npkeith (Oct 2, 2007)

I commented on the 4nm difference in my post. I'm really interested in whether my math is right.


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## Corona (Oct 3, 2007)

It will work - the 4nm difference is well within typical KTP conversion range - here's a KTP manufacturer's take on it:



> Pumped by Nd-doped lasers, KTP OPO has obtained above 66% conversion efficiency for degenerate conversion from 1060nm to 2120nm.



Claims of up to 80% conversion exist in the literature, at 1064nm.

See this link for more: http://unitedcrystals.com/KTPProp.html

The math is correct, 3J = 3 W/s, and flash duration is a function of capacitor size (e.g. plasma lifetime in the flashtube) and sounds about right for a 100W/s xenon flash. 3 watt-seconds is the OUTPUT of the rod, it probably takes a few hundred joules in the flash dump capacitor to result in a 3J output, due to the low conversion efficiency of solid lasers.

So yeah, 3 megawatts for one microsecond = 3J. 

To calculate energy stored in a capacitor, the equation is J = 1/2 CV²

Units are Farads, Volts and Joules.

Obviously, there is a huge advantage to a high voltage capacitor due to the squared voltage term...


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## lazerlover (Oct 5, 2007)

How can I build a green laser with a capacitor, can anyone help with this?


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