You have make the crystals in perfect place and keep it there and dont forget keeping the diode still housing it soldering batteries and all that stuff but crystals and tech are the hardest but alinging them that super annoying.
Nd:YAG and ND:YVO4 can both be used in combination with LBO in order to get 473nm. However, the 946nm line is quite weak compared to the 808nm. It will take much more then 2 watts to generate 500mW 473nm unfortuantely. I would be happy with a stable 40mW from this.
Most YAG rods are..well rods, this looks like ND:YVO4, which is more efficient anyway. However you need to be careful with ND:YVO4 and how much pump power you use, more then 2 watts will usually cause grey lining over time, which is why YAG is normally used when the pumps get to this power and higher.
For a standard lower-power green setup the order is: pump diode => beam correction lens/optics => Nd:YVO[sub]4[/sub] => KTP => OC
I've never built a blue system, but know that for 473nm they use Nd:YVO[sub]4[/sub] or YAG plus LBO instead of KTP.
For the most practical DIY system I recommend using composite or hybrid crystals. These contain both Nd:YVO[sub]4[/sub] and KTP along with all necessary coatings in one small crystal. Then all you need is a pump source and an output lens. This minimizes the amount of alignment necessary to achieve a decent output with good beam quality. They can be obtained on ebay premounted in a tiny heatsink here: http://cgi.ebay.com/Nd-yvo4-Ktp-Glu...53141QQcmdZViewItemQQ_trksidZp1742.m153.l1262
I found another nd:yvo4 crystal but it says coatings = HR-1064/532, HT808 S2: AR-1064/532
So I couldnt use one like this to make blue right? I would have to find one coated 946/473?
Also, I have seen some using a "BiBo" crystal... what is the best to use for pumping 1w of 808nm(T05)?
Curious... What does each crystal do? why do i need 2?
I hate to rain on anyone's parade.... but getting any blue out of a 1W T-O5 will be very very impressive.
There is a reason these blue lasers cost so much, and it isn't materials cost. Blue is very hard to make. I have a 2.5W c-mount pump with a yag and good sized LBO, all with the correct coatings. I've made a lot of crystal sets lase green (and no, not bonded sets that you just stick in front of a pump and get green. The ones with separate components and OC's that need to be aligned perfectly) and I've yet to get more than a mW of blue. Alignment and stability is very tough on a 473nm laser, everything (alignment and temperature) needs to be flawless to get any sort of respectable output. You'll need custom machined mounts to hold everything in perfect alignment, and then be able to adjust them on top of that.
I'm not saying that it cant be done, but just know that its much much much much harder than green.
for 500mW of 473 you're looking at around 10W of pump power, or more.
Also if you are going for a 'hand-held' design, which is even tougher than a lab-style, I think most pointers use BBO crystals.
You'll need a yag coated as follows: [highlight]S1[/highlight]: HT: 808,1064,1319 HR: 946/473 [highlight]S2[/highlight]: AR 946, 473
Then you should also have your doubling crystal coated on both sides for AR 946 and 808
Then your output coupler needs to be Plano concave with an ROC of 50 to 100. [highlight]S1[/highlight]: HR 946 HT 473nm [highlight]S2[/highlight]: AR 473nm
Thanks for the info!
I will have my CNC mill done sometime in april.
I am building it as a dual-purpose, PCB & Aluminum mill with great accuracy. 4'x2'x4" travel!
So with that, I can achieve near perfect positioning... I will integrate fine tuning capabilities.
yeah, works the same. Have you built one? Probably not if you think it's as 'easy' (which still isn't easy!!) as green.
Gain on 946 is much less, it's harder to get the line to lase, not to mention polarization on green doesn't really matter, or at least not as much. It DOES with blue. If the roation of your yag or LBO is off by just a little bit, you wont get any blue. Also, with green as long as you have a clear optical path through the crystals you can probably get it to lase, with Blue or LBO in general, there is a specific path in the the crystal that will allow for the best amount of blue. Also temperature is a huge factor, if your LBO is too hot or cold you wont get any blue at all. There is much more that goes into a blue than a green laser. Like I said before, materials aren't that expensive and yet blue is still a lot more expensive than green.... why do you think that is?
Also, you said there's no 'need' to build a 473nm blue since 445nm diodes are getting cheap. If I 'needed' a blue, I would buy one. When you make one you should be happy if you get any sort of light at all. I'm not building one to make some super strong badass laser, I just want to do it because I'm very interested in the science behind it and the challenge that is associated with it. I already have a 473nm blue that I bought that does close to 200mW.