Optima lenses

**planters** · 03-28-2011, 18:08

No. When I checked them out I ordered 2 and the tap and they were OK with that. I subsequently ordered 20, but they did not anticipate that prior to filling the first order.

**dsli_jon** · 03-05-2012, 15:33

Hey Kats -

Sorry for the necro-post, but:

Originally Posted by edison

..O-like lens has good results but the beam at aperture is about 5x5 instead of 3x3

Is this data for Reds or Blues.. or Both?

Looking to find-out who has tried both lenses, for multi-watt knife-edge bangers, and has data as to which, of the two, gives a smaller beam-profile, especially for the FA, at-aperture... for our favorite 'infamous' 445 Blues..

..also, how the Optimas perform against the O-likes for internal-losses from eachs' particular AR-coating.. the Optimas, having a 'design ~ or 780nm, and using MgF2, vs the stuff, ie: Edmunds uses for either VIS-0 or 'CDAR'...

Thoughts? Data?

Much obligeded..
j

**logsquared** · 03-05-2012, 16:02

I don't have my notes in front of me but here are some rough numbers..
The o-like blue lens gives ~2X5mm at aperture with 1.8mRad. The optima 4mm gives ~1X3mm at aperture and had twice the divergence of the olike. The optima gives roughly 10% more power. The 405-g is slightly better than the optima probably because of the 445 specific coat. .... But the difference is small. I have a power measurements with the o-like blue in .005 inch increments if you want I can post them later.

**dsli_jon** · 03-05-2012, 16:17

Sir Log..

Cool, thanks.. So, are you saying that the 405-g is 'slightly better than the Optima' in power-output, as-well-as (..at-least..) roughly the same div. specs?

..In other words, sounds-like the O-likes are 'better' for 1-4 bangers, where better beam-div is more desireable than over-all power... (which is why we settled on them..), but for knifing, say, 10+ diodes

where you are trying for max-power, at the expense, perhaps, of a little 'poorer' div.m would you say the Optimas / 405-g's are *comparable*, divergence-wise, not just transmission-efficiency-wise (better coatings, etc)?.

..If so, sound like it might be worth a shot a trying the 405-g's, where a smaller size, at-aperture, is more desireable, since we will be able to pass 'more of the meat' across the multi-mir set-up, albeit at the 'cost' of a slightly-poorer div... (..which, in our case, is fine, since this will be 'blended' with an approx. 8mRad KTP beam...

Your further O-like data, too, is highly-appreciated..

j

**logsquared** · 03-05-2012, 16:29

optima and 405 g are within a few percent beam size wise with the 405g having a slightly better looking spot.

8mRad. damn! I don't think 10 diodes is gonna cut it at 4mRad (optima)

what size are your mirrors?

**dsli_jon** · 03-05-2012, 16:45

TBD, exactly, but will be at least 14-15mm.. And, we will have to 'play' with the post-combo'd beam, (..as-do other 'commercial' hi-watt combo'd-modules..) to see if / how we can 'better' the div. if-even just a bit.. same-way the cylinder-pairs, are used, post-lens / knife.. I've got a couple 'candidates', in-mind...

RE: '405g having a slightly better looking spot', I assume you're talking 'far-field'? And, what does 'better looking' mean? 'cleaner' / less fringing / funk? Or, 'rounder'?

j

**planters** · 03-05-2012, 17:00

Jon,
As you know I've used the Optima 4mm aspherics for the LOCs. They give a 2x3mm beam with 97%vs. raw for the throughput with a PRACTICAL 0.7 mrad divergence uncorrected. I think I have a few lying around along with Dave's 9x 0.5mm barrels. I have never tried these with the 445s, because I love the O-like for the blue. Aside from their $7 price they have a 0.7mm x 4.5mm strip that a normal human can stack. Any smaller at the aperture and I think you'll give it back in the stacking gaps. 1.7mrad x0.3mrad in a 9x5mm stack ( you can do that ) after the PBS then cylinder lens out to 9x10 to match the slightly astigmatic KTP beam and cut the divergence to 0.85mradx0.3mrad.

**logsquared** · 03-05-2012, 18:49

Here are some measurements I took with the same diode. Both are taken with the same diode at the same current. For some reason I didn't record the current. Basically I ran the beam through a pair of calipers 2" from the lens and read the power.

405-g-2 SA
.100" 760mW
.095 760
.090 758
.085 760
.080 761
.075 759
.070 759
.065 757
.060 755
.055 750
.050 746
.045 739
.040 719
.035 692
.030 637
.025 580

Fast axis
.200 760mW
.180 760
.150 750
.145 748
.140 744
.135 738
.130 735
.125 731
.120 720
.115 716
.110 706
.105 701
.100 684
.095 674
for some reason i skipped a few.
.075 590

O-like SA
.115 735
.110 733
.105 733
.100 733
.095 730
.090 727
.085 728
.080 725
.075 715
.070 705
.065 690
.060 670
.055 641
.050 615
.045 575

FA
.200 733mW
.195 733
.190 732
.185 725
.180 716
.175 715
.170 708
.165 700
.160 690
.155 678
.150 672
.145 655
.140 650
.135 635
.130 625

Dang that took a while to type!

Data says 733mW/760mw X 100 = 96% for the o-like compared to the 405. I remember thinking it was more like 90%. Maybe at 1Amp (can't find those numbers right now)
Should be noted that these diodes are different from one to the next. On thing I have noticed is that the SA gets roughly larger proportional to current until about 1.2 amps then on some diodes it "jumps" back!

I am thinking go with the o-like. In theory it would be 4X brighter at a distance than the optima or 405g per diode. But if you're dealing with 8mRad green that's a tough one to decide. I think you would need so much power at 445 spread out over 8mRad to even come close to matching the scope.

The 405g has a better far field spot than the optima. Its just a observation, really doesent mean anything really. Like the focus is more even across the spot (line)

If you are going to build it on the scope deck I have an idea you probably already thought of but will mention anyway... Use the water loop to cool the base of the 445 set-up. This will help keep all the mirror mounts in alignment.

Also, I can send you a sketch of a really stable easy to build mount that should do you right for 10 or 20 diodes. (I think I remember you posting that you have a mill)

**dsli_jon** · 03-05-2012, 19:39

hey LS -