Well, NairB told me to check out this post, so here is what I have to say.
Senkat, do you have any idea what you're getting into? 50W to green sounds pretty awesome if it worked, but I have a feeling there's a lot you're forgetting.
First off, you do not have a 50W 808nm diode. No such thing yet to my knowledge. What you have is a 50W diode ARRAY. Its many diodes side by side basically. To power it you need a lot of power from a PSU that is accurately current limited. That's the first of many many challenges. Next you need it liquid cooled and fully heat sinked or your diode will be trashed. That's just getting the pump working.
Then you need, not Casix crystals, not regular YAG or KTP crystals. With this much power, there's no way you can just shine it into a crystal and get green, especially since its a diode array and you're not getting 1, but many beams. What you need is a YAG crystal that can be side pumped, and a good one. We're talking thousands new, maybe in the hundreds used. That will probably need to be reflective on one end, partially reflective on the other. Then you need KTP or something of the sort, reflective to 532nm and antireflective to 1064nm on one end, partially reflective on the other. For those powers, you're once again talking a lot of $$$. Then each crystal needs temperature regulation to keep it not too hot or too cold.
The diode array also needs optics for the pumping, and the whole system needs to be perfectly aligned.
All in all, a project only for extremely advanced engineers in the field that I wouldn't really have any idea how to start, and one I highly doubt you'd get 10% through before breaking something, or needing to give up.
IMO: First, you should start from the basics. Casix hybrid ND:YVO4 and KTP from a leadlight or something and a small 808nm diode. That in itself can be challenging for a beginner, but it looks like learning to flip a light switch compared to the above project. You'd definitely need to tackle this first before considering that 50W - green, or just as bare 808nm.
Also, heurrsciences is not a reputable seller from what I've heard. I've heard of some people getting good deals from him, but also read some very very interesting stuff. One such "interesting stuff" regarded him throwing acid at the police attempting to arrest him, and another involved some scams on crap gas lasers.
Anyways, you definitely have a noble project in mind, and one I'd definitely envy in its finished form. However it's also far too ambitious IMO. Start from the basics and work your way up. Maybe someday you will complete this monster laser and I will bow down and kiss your foot, but for now, learn a bit more about the processes involved, and start small. Maybe buy some books on the subject? Good luck!