2fl Dave's lens on 445

[The_Doctor]

diode i tried was m140 445nm , at 2mmfl i doubt any light missed the lens , i think its down to the fact of the ar coating is for red and not broadband.
for my builds i use the g2 len along with cylinder lens set , or an olike lens with a prism set if the build is more than 2 diodes combined

I asked Dave to confirm about coating, and I thought he said BBAR. To be fair, that might have been about the cylinders, not the 2mm fl lens.

So does this mean a call for 2mm fl with blue-coating, or BBAR? Also, I'm not sure why the question didn't get resolved earlier, like it did for red.

Edit: I'll go with that advice about the cylinders with 405-G-2. I did buy some prisms to try from Andy but still no arrival yet, but unless I really need the flat surfaces to correct a lot of beams (unlikely) the lenses will work better for me I think, for ref or blue. (Is why asked about BBAR in the first place, I wanted to be sure I could do that.) And with 25 G2's bought, got to use what I have now..

[logsquared]

I didn't see losses anywhere near that bad.

check this thread. http://www.photonlexicon.com/forums/...785#post221785

[dave]

So does this mean a call for 2mm fl with blue-coating, or BBAR?

The 2mm lens has a 637nm specific coating.

[The_Doctor]

Ok. Thanks. Was there any call for a blue wavelength coating? I'm not sure whether this question is only arising now due to a new diode, or whether it's been done to death two years ago or more. It looks like logsquared's results (actually in a post a bit higher than the one linked) look good. I don't know what it's like after cylinder correction though.

I'm guessing the more widely used choices were made for beam spec matching rather than ideal beam quality for one colour.

[planters]

I really like the stock lens with the 9mm 445s. As long as it is a single diode or a PBSed pair, I expand this beam with a -25mm cylinder and a +100mm cylinder and the result just fits a 5mm aperture scanner. At 12.7M the spot is 3mm by 6mm. The loss with this much expansion is lower with the lens pair than with the prisms and the stock lens has about 15% higher throughput than the O-like.

[The_Doctor]

What means 'stock lens'?

[DTR]

It is the lens that is attached to the diode in the projector.
http://laserpointerforums.com/f65/ne...des-73284.html

[The_Doctor]

Oh right, that occurred to me but I couldn't beleive it because I thought it didn't have very good properties for collimation. (Based on stuff I'd read, I never had one).