The Big Green Thread (I'm gonna regret posting this in the morning)

Fedex really dropped the ball on this one...

"Could not find the street"

Yet the book I ordered showed up on another truck, also Fedex Ground.


Steve

Quotes came in on the Vandate without Gd doping. 89-110$ a rod plus a 60$ fee for ordering, for any Quantity 1-10. Planters specified two types, one with a diffusion bonded undoped end, so 89$ or 110... The diffusion bonded end works wonders for reducing thermal lensing. The undoped portion acts to cool the end of the rod. Diffusion bonded means its one solid crystal with no glue when done.

We're now waiting on a quote for the same scheme with ND:GdVo4. Better conversion and less polarization issues.
You won't find a diffusion bonded rod on Ebay... This is starting to look like a winner....

Rods are coated both ends AR 808 and AR 1064 allowing for double ended pumping.

Rods are cooled, KTP is cooled...... TE optional on the KTP, they used water. The rod is in a water cooled copper block. Due to resonantor layout reasons, water is a winner. There will probably be less then a litre of it.

Right now what I know, Minus Shipping/customs fees/whatever...

Pump diodes ~400$ Each
Basic Rod 110$ Each
KTP 135$ Each
LBO Option 330$ Each

2 watts will be single pump diode. Other design for 4-5 watts will be double diodes.

Design M^2 quoted in the paper is 1.2 to 1.5 depending on optics options, if you throw away a little power you get TEM00 and a better M^2.

Need 2 get optics quotes next....

The above is a forward looking statement....

Steve

Wow, sounds like it's coming together! Thanks for the info Steve!

So it was supposed to be hold for pickup again....
After driving to a obscure Fedex facility, going through "airside" type security with pat-down... After being searched and ID, I was told to stand in a streetside corner of the security shack and use a phone... To be told the diodes were not held as promised., but sent to my house... Waste of a hour, as we're driving to see mom's sister tonight...

So I have the diodes, I brought the data sheet and test sheet with me:

At full power.... One sample is:

Pout(Watts) 7
Iop(AMPS) 7.92
Ithreshold 1.13
Slope Eff (W/A) 1.01
Eff At Iop 42.32%
Max Eff 43.79
Rs(milliOhms) 64.6
V@Iop (Volts) 2.09
Wavelenth at Tc = 25' 810.8 nm, centroid 810.54 FHWM Power 90% = 2.34 nm

Temp range restricted to 20-25'C. The baseplate part of the package is 10x14 mm, with about 6 mm out of the 14 being the bolt circle, with far less heat.

Steve

Off-topic fyi -

Quote:

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Originally Posted by macona

That's odd, I have had several items held for pickup with FedEx ground.

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The 'official' rule is, FedEx Ground will not be held at a FedEx Express station, unless expressly-authorized / exception-made, by that-location.. The 'official' stance is, Ground Holds go to a 'FedEx Office' or Ground-only stations, again, unless you get the local-place to 'bend' that rule for ya - not 'automatic'....

Sorry you had frustrations, Steve - they should have told you that..
j

steve in the interest of learning can you help me undersand somthing
the m3 mirror in this design r=100 hr1064 ht532 ar 532 .
later they mention about using different coupling ? not understanding to well do they mean for example 15% is that transmit 15% green ?
or transmit 15% 1064 ?
if its transmit 15% green where does the rest go ? surley that would mean m1 or the nd: would need an hr532 coat on it, i am lost
please help

thanks

Quote:

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Originally Posted by mixedgas

I'm attaching another paper for educational use.

This is not the final design either. There is something else better in the pipeline. It does give the discerning PL reader a LOT to think about.

This is one that I would consider building if I already owned a older, working, FAP. Its not bad, but its not state of the art.

The beam quality is, however, not bad at all. In fact its better then most currently made low cost lasers. Because many of them are side pumped. Side pumping is horrendous at 1-2 watts of green. However it is cheap to build. That is why we put up with commercial lasers with shifting modes and horrid modulation.

We'll discuss this at a later date, I need to get to work.

Liu, et al, Optics Communications Volume 173, 2000, is attached for educational use for a short period of time.

Steve

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I think you'll find if you reread that, they were leaking IR for diagnostics. Its probably reflect 100% IR transmit 100% green. Ie S1 is HR1064 TX532 with HT532 on S2
Thats not the paper we're going to use. Better is in the works.

Happy Thanksgiving Day from us Rebel cousins!

Steve

I dont want to insult the vendor, but they used Ground, Not Express.... Some one at FEDEX should have told them.... :-(
Steve

As per the vandate polarization dependence, just polarizing the diodes at 45degrees doesn't help much, it just means half of the light for each diode gets absorbed too quickly instead of all of the light of one diode. That said, if you make the spot size large enough that you do not get excessive thermal lensing even with the much higher absorption you can make it work. If we are using fiber coupled diodes and end pumping from both ends we should be fine, even if we do try for combining the two diodes with a PBS for single end pumping (makes the green extraction a lot easier) it might be possible to make things work out as long as you plan ahead.

Its great that you have decided to switch over to fiber coupled pumps, even if $500 a diode is pretty steep when you need 2 of them. I wonder if it would be worth it to investigate getting the fiber bundle type bars and put up with the .8mm fiber, which opens up the posibility of buying cheap surplus pump diodes on ebay as they turn up. It would mean that we have virtually unlimited pump power available (can get 40w sources if you need them). In any case you should be able to do a lot better with the astigmatism, just make sure to use a flat mirror for the folding mirror and everything should work out great.

As per 880nm, running at 880nm you can win at bit with reduced thermal lensing and on the quantum efficiency, but for 10-15w of pump power you are probably better off putting up with the bit of thermal lensing and not needing such a long crystal. At 880nm you are talking 10-20mm crystal lengths at 1-2% doping, our systems run with ln2 cooling which makes the problem even worse (absorption band is less than 1nm), but even at room temp you have to go to pretty extreme lengths to get good efficieny so it really is not worth it at these power levels.

It will be interesting to see where this goes, it would be neat to see where this project ends up going. Is the current plan to have steve do the initial testing, and if things are looking good on his end then go through and start buying pieces and thinking about CNCing the casing?

Quote:

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Originally Posted by krazer

It will be interesting to see where this goes, it would be neat to see where this project ends up going. Is the current plan to have steve do the initial testing, and if things are looking good on his end then go through and start buying pieces and thinking about CNCing the casing?

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I offered up early on to assist in some Solidworks designing and also CNC time as well. To premature possibly for this but I am waiting on the sidelines.

Ivan