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

[mixedgas]

I was specifying nylon simply because they will yield under small forces and flex in more then one axis. Steve-O, you just want to lightly clamp the MCA once the Indium caves in. If you go with Bellville or Wavy washers, you might want to buy a bag of the weaker ones and stack them to ensure a light retaining force. If the crystal has a thin edge vertical in your design, have a thin ridge at the bottom sticking out of the copper so the crystal does not slide down out of the mount under gravity.

Properly stacked Bellevilles look like this <><><>

If you have a friend who can mill out a square pocket in the copper for the crystal, leave a gap at least twice the thickness (or more) of the indium sheet around the edges. Make sure the MCA is slightly "proud" of the copper on the output side by .005 or so, that way you can clamp it.

Steve

[mixedgas]

Looks like pumping with domestic sourced, overseas made, dual fiber pumps may come in a bit under 900$ per system (for the diodes) if we can build five systems. It could actually be a bit cheaper then this, but I'm padding the group buy price a bit for shipping and a bit of profit. Whom-ever has to manage a group buy of $5,000$ worth of stuff needs to make a bit per transaction for gas money, and the aggrivation of dealing with a bank, taking half a day to do a wire transfer, half a day of trackable shipping etc. Going to dual C mounts is ~1250$ a system after some padding.

Steve

[badger1666]

maybe usefull titbits of info from sam's faq

[steve-o]

Just want to say thanks again Steve, planters and badger for the advice on the MCA project . I'll post (on a separate thread ;] any progress that may occur. Now back to the 2W 532 DPSS thread, already in progress. No more thread-hijacks, I promise

[mixedgas]

This email may contain forward looking statements.. Blah disclaimer...Blah

And Steve spent too long on the phone with Planters to get the design docs converted to PDFs tonight... However that phone call gave us better options.

Good news, we found a good source of KTP and LBO.
Planters has a option on a easy, peasy group buy on pump diodes from a US vendor at a price that is actually less cost then 3 watt Ebay C-mount diodes.
They are not made in the US, that tripples the price, but they are packaged and tested here.

Pump diodes are ~200 uM fiber coupled, 7 watts. Minimum 10 units.

The source will sell us two at the group buy cost for trial, and those two are in stock.

The papers we looked at were all 1.5 mm core fiber based. We have a 200 uM core in the new diodes. That's a boost of 20X in pump density in the crystal. For short lengths of fiber, the vendor states the polarization is kept, reasonably well. I do need to check the NA, but its better then the 1.5 mm fiber used in the 3.6 watt paper.

I have a suitable chunk of coated Vandate for the trail run. I know where to borrow the long KTP from, a medical friend has some.

That means we need 2-3 cavity mirrors, and a wavelength seperator dichro to get started. Plus I need to build some 20 amp diode drivers.

We're going for a prototype! hum, typical 33% conversion from 7 watts to 532 is 2.31 watts from ONE diode using the 1.5 mm fiber numbers.

The price numbers were shockingly good for a 2 watt. On a par with the Chinese units, (not counting any machining) but with better beam quality.

We also know that in less then 2 years these will be obsolete except for superb beam quality when doing graphics. But that is 760 days away.


Steve

[steve-o]

We're going for a prototype!

Woo-Hoo a prototype!!

The price numbers were shockingly good for a 2 watt. On a par with the Chinese units,

So, that's going to be approx somewhere around 2-3k USD? .. or is it too early to tell ..

We also know that in less then 2 years these will be obsolete except for superb beam quality when doing graphics. But that is 760 days away.

Bah, humbug .. these will be forever non-obsolete, I'm sure

[mixedgas]

I still need to get Vandate quotes, Steve

[planters]

Steve,

After looking at it again, I do like the 3.6 W paper. It seems conservative because we should meet or beat the diode input power/quality. I am planning on starting with two 808 diodes. One as a back up sure, but I am not convinced as I discussed above that the birefringence is going prevent us from PBS'ing two of these. If it does then I suggest we look at inserting a 45 degree 808R/1064P dichroic on the other end of the Vandate and double pumping that way. One advantage of the double end pump is that it ameliorates some of the cone angle mode mismatch from the opposite end, reduces the local intensity for a given power level and probably to some extent balances the mechanical expansion forces along the Vandate rod. Furthermore, if the PBS is not a problem then dual end pumping would open up the possibility of 4 pumps...

I haven't asked about the possibility of 888nm pumps. This depends on whether the absorption is broad and good here as it is at 808 ( Vandate is not birefringent at 888nm).

[mixedgas]

The pump spectrum is narrower at 888. I'm working on it.

Steve

[Meatball]

Common sense tells me that 808 is better since it is widely available and more easily replaced. This ought to make it cheaper. Is this really so wrong to assume?

Sam recommends no pumping with anything from 830-870. No mention of 888 by him or by anyone.. then why consider it here? Isn't a broader pump spectrum better?