How to calculate the amount of watts of 808nm it takes to get 5 watts of 532nm.

[Fotobysw]

Hi guys;
I know that this is out there somewhere but I am going to ask anyway.
Does anybody know how much 808nm it takes to get 5 watt of 532nm ?
I need to build a high power green for a projector I am designing.
So I need to figure how much 808nm it will take to achieve a specific amount of 532nm.
I am using a crystal set-up from a Spectra YAG laser that has a active peltier cooling with a water cooling block so I think I should be able to get a high 532nm output.
Is there a formula to calculate the 808nm to 532nm power output?
I am sure it also depends on what crystal system you are using so if I can get a ballpark idea then I can work from there.
I know ,with the amount of laser knowledge on this board, someone should have the answer.
Thanks
Steve Wall

[mixedgas]

Its not that simple. You need to know the host material and its doping, adsorption cross section, and preferred pump polarization. Then you need to know the desired beam waist in the crystal to match the existing optical scheme. Too much pump is very bad as well. A guess may be as much as 45 watts or more depending on model.
Steve

[planters]

I am in the process of finishing a vanadate based 532. With a single (of two) 10 W pump I am seeing 2.5W out. Because of the threshold, non-linearity and because the slope is >1, I expect to approach 6W with 20W input. This is why I am moving to greater input with fiber coupled modules because the crystal should withstand significantly higher pumping.

That was the good news. Now the bad. Steve is extremely correct. I have some experience behind me and this was VERY HARD! I will be doing some videos in the next couple of weeks highlighting the issues involved and demonstrating this laser. You might want to wait for these before you make more decisions about the design, components or even whether to proceed.

[Fotobysw]

Thanks guys. I hope to have the crystal set-up in a couple of weeks so I should have more info then.
Steve Wall

[steve-o]

Been looking forward to seeing a vid or posts of "Big Green" progress from both you and Steve, Planters. I know you both have been working hard on this project. I need to get an 808 w/ FAC and break out the MCA again .. oops I shouldnt have said "break" heh .. wrong word .. knock on wood ..

[planters]

I think you should go ahead with the 808nm with FAC and try the MCA. The project has become something like a graduate level course on laser opto-mechanics. It often ceases to be fun and is certainly not a less expensive route to a couple of watts of green for a projector. I would love to hear about your progress good and bad. This would be a refreshing break and inspirational as well.

[steve-o]

Sorry about the threadjack Fotobysw.. I'll xfer this conversation to the appropriate big green thread after this.. @ Planters, yes I got a high power 808 from junktronix but it didn't have a FAC lens. It was something that I didn't think about. The one I originally was experimenting with did have the lens. The new setup didn't work, so I put the project on hold. I'll hunt around and see if I can find a good 808 w/ FAC and resume where I left off..
Cheers..

[VDX]

... you can get away with a single standard lens, when using fiber-coupled lasers.

I have a 25Watt@808nm-diode with 0.8mm apperture and can collimate or focus the beam with a single lens to maybe 0.7mm.

For material processing I'm using fibercoupled 975nm-diodes with 0.1mm apperture and powers from 5Watts to 25Watts.

Attached two images of one of the 975nm-diodes with a single plastic lens for focussing at around 7Watts optical output ...

Viktor

[mixedgas]

I have to disagree..
He's not likely to get away with a single lens at 5-6 watts of green. He needs a controlled, long beam waist, not a focal spot.

Steve

[planters]

If beam quality isn't a big driver then the hassles I am dealing with might be avoided. Let's say steve-o uses a short, simple lens to take the FAC down to a nice small spot with a correspondingly very short depth of focus. This is easy. Then with a high doping concentration and the short cavity of an MCA, the thermal lensing might not be too much of a problem. Pump it until it breaks. Then for the finished laser, if the MCA is vanadate, the polarized output could be combined with a PBS to achieve twice the power.