Conceptual design of anamorphic prisms on sinner focus ring. Pix!

[CDBEAM777]

Well...Some progress with the testing of the Cylindrical lenses supplied by Tomorrow Systems. See attached pics. Sorry I have bad results with the farfield shots showing the beam geometry. Blue saturation issue as typical. Perhaps I will try some type of camera lens filter ?? Regardless, the metrics posted are accurate. It should be no surprise that cylindrical optics do correct the elipiticity of the NDB 7875 LD. Not perfect....but better.

Test was done a 1.5A at 4.5 VDC using the NDB 7875 LD. Farfield target at 25' (7.62M) from LD aperture. LD geometry at aperture @ 2mm. Collimation lens used is the O-like glass. Cylindrical lens to lens positioned at 12.64mm separation. NO detectable loss of power thru the TS optics was seen. Meter used is a calibrated Sciencetech 362.

1) Beam geometry at 25' (7.62M) with no TS Cylindrical lenses observed at 15.2mm wide by 3.75mm tall. This equates to a 1.73 mRad.

2) Beam geometry at 25' (7.62M) with TS Cylindrical lenses observed at 8.34mm wide by 3.75mm tall This equates to a .831 mRad.

The take-away should be that these Cylindericals work as advertised. That said, I think the real benefit of using Cylindrical lenses will be with the diodes with very bad raw divergence. Great candidate's for the Cylindricals would be;

1) NDB 7A75 3.5W Blue
2) NDG 7475 1W Green
3) NDG 700 .7W Green
4) HL 63193 .7W Red
4) ML507P73 .5W Red

These above laser diodes are the " Bar Generators " and really need adaptive/corrective optics. I have the HL 63193 Red and will give it a trial with the TS optics. Expect some results by mid-week.... All this testing will support the end geometry of the nex-gen EZ adaptor....so that is where this is leading ! Oh...And...Lite'em up !

 

[VisibleGreen]

CDBeam shouldn't you test with the G2 or S1 lens?

 

[Tomorrows System]

They will work the same way with almost all collimator lens.

To make some beamspot pictures use the flash in your camera and narrow the aperture also shorten the time of making the photo if possible, then you can receive the photos I'm making.

What is the EFL for olike lens? I was making the tests on quite standard three element lens.

If you use exactly this lens on P73 or 3,5W 445nm you will have also 2x divergence correction but for this diodes the other lens should be use and they can correct it more than 3 times. Problem is that if you use >3x beam correction on the 1,4W 445nm diode you will have at the output something around 9mm wide beam what is quite much, but will also work and lower the divergence

 

[VisibleGreen]

Yeah but you get a tighter beam at the start with a single element lens so I figured it would provide better results.

 

[Tomorrows System]

With single element lens beam can be better at close distance, but at long distance I think it will be worse. Single element lens allows you to obtain really small close field beam spot but also at the cost of divergence. So when he usise G2 instead of three element he will get lower divergence but smaller beam spot at near field.

 

[CDBEAM777]

Optics are always about trade-offs ! I initially tested with the S1 lens but, decided to stick with the O-Like lens. I might repeat the test with the S1 lens ? As Mateusz noted, the correction of the TS lenses will be the same ! The S1 lens presents an initial larger divergence at 25' (7.62M) than the glass O-Like collimation lens. The TS optics do there job, but when you start out with more divergence ( wider bar), you end up with more divergence ( wider bar). It is all relative. I do not know what the EFL is on the O-Like optics.

SO, the trade-off I am referring to is one of power. The S1 lens kicks the PO up about 5%,over that of the O-like lens ! ...But at a cost of greater divergence, at least at the 25' (7.62M) target. I do not know what takes place at 500' ( 152M)....and really have minor concern over this. Perhaps at much greater farfield, the S1 " catches up" with the O-like and has equal beam geometry? Dunno ?

I think for general purposes, what is presenting at a 22' to 32' (7-10M) distance is most relevant ?? That is just my opinion.

 

[VisibleGreen]

I'll have to read about the optics tests on PL again. They tested these kinds of optics already and got better results with even the G1 lenses. Let me get back to you guys on that.

edit Is that you CDbeam on pl? lol that was back in 2011! Yeah I knew the divergence would be worse but I could have sworn I've read better numbers with the optics from dave on pl with the single element lenses were much better but I'm not too sure now.

 

[CDBEAM777]

I'll have to read about the optics tests on PL again. They tested these kinds of optics already and got better results with even the G1 lenses. Let me get back to you guys on that.

edit :O There's like 55 pages to read ... fudge

Hmmm....You must be referring to the " Holy Grail " Thread....I wonder who was the " Rocket Scientist " who started that thread ??? Hahahahahaha ... IIRC...with the P-73, one can achieve about 1.1 mRad with cylindricals....and that diode is about the worst you will find as far as nasty raw divergence.

Yes....with the P-73....the best collimation lens, in my opinion is the 2mm EFL from LSP....but, we are just speaking about the P-73....not any other LD. For the 7875 or 7A75...IMNSHO....the S1 or Olike glass.

 

[VisibleGreen]

Hmmm....You must be referring to the " Holy Grail " Thread....I wonder who was the " Rocket Scientist " who started that thread ??? Hahahahahaha ... IIRC...with the P-73, one can achieve about 1.1 mRad with cylindricals....and that diode is about the worst you will find as far as nasty raw divergence.

:crackup: Yes sir that's the one. Also about the olike lenses, don't they just clip the output rather than collimate it better? I mean don't get me wrong, I use them for my 445s and it's a great alternative for the crappy divergence and beam specs.

Edit So the P73 is even worse than the new nbd7a78?

 

[CDBEAM777]

:crackup: Yes sir that's the one. Also about the olike lenses, don't they just clip the output rather than collimate it better? I mean don't get me wrong, I use them for my 445s and it's a great alternative for the crappy divergence and beam specs.

Edit So the P73 is even worse than the new nbd7a78?

Yes...I believe the O-like clips the raw beam alittle,,,and that is why it lowers the output power a little also....Always trade-offs !!!

Eh...Ahhh...Dunno....I do not have a NDB 7A75 to experiment with...but I believe it is almost as bad as the P-73...The 7A75 LD is on my wish list !!! as are the high power green's !!

 

[VisibleGreen]

Yes...I believe the O-like clips the raw beam alittle,,,and that is why it lowers the output power a little also....Always trade-offs !!!

Eh...Ahhh...Dunno....I do not have a NDB 7A75 to experiment with...but I believe it is almost as bad as the P-73...The 7A75 LD is on my wish list !!! as are the high power green's !!

Same! Prices are just too high right now though so more waiting it is ...

 

[The Lightning Stalker]

Edit So the P73 is even worse than the new nbd7a78?

Yes, mush worse. The ratio between
parallel and perpendicular is 3.2 for the
NDB7A75 and 5 for the P73. The award for
the worst raw divergence I've ever seen
though has to go to the LAZ650C. You could
drive a truck through it.

 

[Wmacky]

Well now I'm chopping at the bit for a NDB 7A75 since I have a host that can accommodate the cylindrical lenses. Unfortunately my wife was just layed off so this may not be the best time......

 

[Tomorrows System]

Yes the 3,5W 445nm has one of the worse divergence ever. But after cylindricals they are better than normal M140 s oactually you got x 4 power density. It is really worth it. I even have one module which is using this diode and cylindrical lens it is really awesome if you need one diode build instead of stacking.

 

[The Lightning Stalker]

Yes the 3,5W 445nm has one of the worse divergence ever.

Yes, the divergence angles are high, but
what is important is the ratio between the
parallel and perpendicular divergence
angles. The higher the ratio, the more
they differ and the more in need of axis
correction they become. If the ratio is
1:1, then the divergence could be horrible,
like 45° or more, but it wouldn't matter
because the lens would take care of it and
the output would still be square.

 

[Tomorrows System]

Yes you are totally right. I didn't compared red and blue diodes just to measure it. For me the most important is final divergence. Also if you want to change divergence x times you need to change close area beam spot size x times. It all depends on what you need.

CDBEAM will you be able to measure the beam in mm to check the exact divergence before and after? It is not something urgent of course