An MCA Thread (this is a continuation of a discussion from the Big Green Thread)

[steve-o]

Sorry Planters, I just re-read your post and I see that you do indeed say

"with dual 10 W 808nm FACs each running @ 8W. "

, so the fast-axis collimation lens is already attached to this diode , right? I'll definitely wait, then ....

[planters]

Steve,

After rereading this thread I have some suggestions. There have been some papers where the thermal control of these end pumped lasers is through the face. This is similar to a disc laser like the ones built by Trumpf. Now, normally the doubling function is not incorporated with the gain medium and unlike the KTP which likes to operate at very high intensities the crystal benefits from the end cooling because this really limits the thermal lensing. The thermal gradient will tend to lengthen the crystal, but will not have a radial component, so no lensing or multi-moding. You should probably use a simple focusing lens on the diode, but start fat and slowly draw the focus in as you watch the green spot size, shape and power. I am almost certain that at 10 W fully focused with a 50mm lens or less that you will be able to drill your chip.

I would also like to try one of these chips with a fiber coupled source to see what that does to the profile. Do you know any sources for these chips? Are they manufactured by several different suppliers and are there different models? Are they expensive?

[steve-o]

The one that I bought from "goodgadgets2u" on ebay is no longer a registered seller there , so I'm thinking that it was a one time surplus selloff. I cna't remember what I paid for it but the package it came in said Casix I believe. It's on this thread. I think I know what you're leading to here; if we build a prototype and the xtal(s) are no longer available due to a custom limited run, it wont do us much good right?

[planters]

Yes, that is one major point. I mean the typical 532nm CN projector lasers are pretty affordable. To justify buying the diodes, lenses and drivers in order to produce a few hundred mW to 2W, you have to have some neat approach that these might make possible. If you wanted to see how far you could push them you need to be prepared to break them. Then others might want to follow. As long as you have one I think you should keep going, just be a little more careful.

[als1980]

Thanks als1980 for the heads-up on those .


.. and the price tag of this set-up is?? (I'm not a large corporation, just a week-end hobbiest with a fairly modest budget for these projects) ..

Well price wise the ocean optics part runs $50-70 on eBay. The science surplus unit could be had for the price of their blue lasers which are $75. If you can't find one I will sell you the lens at cost..$20 or so.. I just can't belive how much power these things are taking. Now I gotta dig my crystals back up and see what I can do with it. They are just so damn small!!!!

[steve-o]

Well the one I bought "claimed" to be able to produce 1W (in the small print) , I really doubt if it'd do that .. maybe 500mw, but due to lack of decent 808 I haven't a chance to fully drive the sht out of it yet..

[steve-o]

Ok now I'm at home after toddy-time (you old timers here know what that means) ... lookout ... I'll probably regret this in the morning ...
Yeah they are small aint they als.. A pain in the ass. Anyhoo.. I don't want to have to fuck with any fiber, any lenses .. anything except for a collimator lens for the output. hell, I'm probably not even going to temp control it . at least for the xperimental stages of the design .. I just need a simple 4-5 watt 808nm diode that will produce a nice square (that's FAC Lens built IN) that I can move into this crystal assy .. really close.. is that too much to ask ????? lol ---/rant (end /rant )

[logsquared]

http://www.ebay.com/itm/5W-808nm-Las...item4ac124547a

I bought one a while back. Came as described.

[planters]

Steve,
You really should plan on a simple lens between the diode and the crystal. Even with a FAC the 808nm will diverge @ 5-6 degrees (rather than 5 x 70 degrees) out of the crystal. At 10 mm the spot size in the crystal will be 1mm in diameter and that is too big. Sure it will glow green, but you will gain a lot of efficiency by being able to adjust the spot size in the gain region

[steve-o]

Thanks Logsquared !! Exactly what I was looking for! I saw these but was unsure of the quality. I'll pick one up. Thanks !