Handheld FAP laser

[maranello551]

Alright. I need some serious input here. I have owned several 5mw red lasers a 100mw green, a 200mw red, and a 1w blue. I now crave more power.
My dream is to take a 40w FAP laser diode and fiber couple it and if possible double it to a visible wavelength from the original 808nm and run it through an adjustable focusing lens. I would then like to insert it into a Mag-lite flashlight host (it will probably have to be the largest), and run it off of batteries of some sort.

Possible at all? For cooling would a cylindrical heatsink the diameter of the Mag-lite's body work with the diode encased in it? Amperage would probably be very high and thus drain the batteries fairly quickly unless you guys know something I don't. I am relatively new here. What kind of eye protection would I need for such a "pointer"?

 

[Prototype]

Terrible idea. Not to be mean, but do you realize the kind of power your talking about? You could maybe use IMR cells to get a minute or two out of this thing, but it's designed to run on a TEC cooled heatsink, not just a chunk of metal. You also have to think about the driver, 40W FAP bars need something like 50-60A at 3.2V or thereabouts. Doubling it would be no mean feat, and keeping that steady in a flashlight? I don't think that'd work out to well. Not to be a dream crusher, but this is a terrible, terrible idea.


Edit: And you'd need to move the fiber launch and fiber coupler all at once, carefully. Any misalignment can't be easily repaired and you risk burning the end of the fiber if one of the emitter/fiber couples becomes misaligned.

 

[maranello551]

Okay then is there any possible way to build something with this sort of power in such a small package?

 

[Leodahsan]

Man just think of the math.. you want a BAR that emits 40W light.
Input Power (IP): 3.2v X 50A = 160W (or 192W if 60A)
Output light (LO): 40W
Output heat (HO): IP - LO = 120W (or 152 if 60A). Damn, thats 120W (or 152W) of pure heat.. way bigger than many soldering irons out there! Try to keep that cold if you dare!

about the small packaging.. enough power to power the bar should be LiFePO4 batts. The best that I've seen outputs 20A, and thats a 1600mAh batt. Think about the 31 sec. runtime.

oh, and thats the runtime just for the bar, excluding driver inneficiency and TEC cooling/controller. all that lower the battery lifetime to.. 10 sec.!
oh lets say you use MANY more batteries.. incredibles 2 minutes runtime with a battery pack bigger than a door.

and.. where to get those KTP/Nd:YAG crystals for 40W IR input and 8~10W 532nm output?

definitly, not your typical "maglight" mod or holiday project.
:beer:

 

[maranello551]

so pretty much i'm screwed. any other way to get lots of power (10's of watts) in a maglite style laser?

 

[Leodahsan]

uuuh.. search for "starwarz power" here in LPF, thats the smaller thing that you will find that is at least "portable".

I think the most possible is coupling two 445 diodes with a PBS to get 4W light.

 

[Trevor]

Why are you even considering that much power in a handheld?

-Trevor

 

[Leodahsan]

are you talking with me?

 

[Cyparagon]

Mister Mike's 10W CO2 is RF driven, so it needs a whopping 300-400W if I remember correctly.

 

[Leodahsan]

Mister Mike's 10W CO2 is RF driven, so it needs a whopping 300-400W if I remember correctly.

yes it is. 307.2W with discharged batts, 345.6W with nominal charged batts, and 403.2W with fully charged batts, thats the input.

 

[HIMNL9]

Uhm, about batteries, you can try to see if they still produce Gates (not "bill" ) "cyclon" round lead cells ..... as far as i remember, they was the only ones rated for 100 times the normal current discharge without damage or blow-up (i mean, a 5Ah cell was granted able to give 500A for 30 seconds without become damaged)

But i'm not sure if they still produce the same high-quality batteries, cause Gates was adsorbed from Hawker times ago, and also if the external aspect of the battery is remained the same (except the name that is becomed "Hawker Energy", instead the original "Gates" one), there's no way for know if the inside quality is still the same .....

 

[Benm]

The high peak capability is somewhat inherent to the lead-acid chemistry. Obviously you can optimize the design for peak applications. Looking at the cell above, i doubt it could do a 100C discharge - those leads are supposed to carry 500 amps?!

As far as portable power goes: I'd agree with leodashan: coupling two 445 nm diodes and driving them hard is the best you can realistically expect. At that point you are still burning 25 watts in heat in the diodes though, so heatsinking them will be a primary concern.

 

[HIMNL9]

No, the cells are rated for 5Ah, and the peak is given at 50A, usually, they are simply granted with the capability to give til 500A for 30 seconds without become destroyed in the process (it's not that you can regularly use it for that current, is that they say you that, also if this happens occasionally, the cell remain able to work almost as normal, opposite to any other lead acid cell, that at this rate become destroyed at the first discharge)

 

[Benm]

Melting the leads straight off counts as destruction for me, although the actual cell might be perfectly fine

At that, some batteries can perform amazing feats. You can even start a car using 10 AA sized NiCd batteries if you have to. Doing so will will require some have duty wiring, but apart from that its feasible... and the batteries actually survice such malice several times before failing too.

Lead acid batteries come in 2 basic varieties: starter batteries and traction batteries. A car battery is a starter type that can deliver huge amounts of current when full, but should never be discharged completely. A traction battery lacks a bit of the initial punch, but can be discharged almost completely without any damage.

This is something to think about when you consider lead-acid batteries to power something: the type that yields amazing initial current often is the type that should never be discharged below half its capacity or so.

 

[Cyparagon]

Yep. It has to do with the number and thickness of the lead plates. Thinner (and more numerous) plates mean more surface area, but a greater possibility of wear.

You can even start a car using 10 AA sized NiCd batteries if you have to.

:undecided: That would be a stretch even for NiMH, let along NiCd, wouldn't it?