Mitsubishi ML520G71...Red Holy Grail or Flashlight Fail ??

[p1t8ull]

Planters, before throwing any cash at it just try setting up a pair of diodes using any old lenses you have lying about and knifing in the focus. PCX or cylinder it doesn't matter, principle is the same.

As I (and it seems Kiyoukan) found out, what happens inside the focus area gets magnified out again after the last objective and it doesn't overlap as well as you would think. For example, try knifing two beams at the focus point and if the gap between the beams is, say 10% of the beam diameter, that remains so as they re-collimate and you end up gaining nothing. They do not overlap as you would imagine..
Adjust them so they overlap as they exit the final objective results in a split beam far field with 10% gap between spots, to make them a single spot far field results in a pair of side-by side beams with a 10% gap between them near field.

Divergence shifts that 10% gap about a bit, but you get my drift.

[planters]

Firstly, I do want to pursue this, but not to just recreate what you have already accomplished for my own jollies.

K,
I'm looking at such long FL due to the effect of lens position/shifting. Do you remember the FL of the lens system you worked with and how did you make these adjustments? Looking at the diagram above and thinking about the typical resolution of a flex- mount as the first stage kneif would this be s significant improvement? Please understand these are in no way criticisms. I am trying to determine from someone who gone down this road how much I would have to do to wring this out, to go further.

P1t,
I had experimented with a rough and ready version of this about a year ago when trying to pack more 445s on a scanner. I tried some PCX lenses and a couple of round cylinders. The off-axis aberrations from the PCX in the orthogonal/axis was annoying and impossible to eliminate, the round cylinders were quite hard to line up. There was a contra-intuitive property that I discovered where a beam that originated from a diode displaced to one side required the beam to be angled FURTHER out to the same side in order to overlap in the far field. This negated any obvious benefit at the scanner. However, I was not using this optical manipulation to temporally compress the beams for the kneif.

Before spending money or time it would be great if some with a optical design program that could input this setup could definitively rule/rule out the worth of this pursuit. Meanwhile, I have trouble with these thought experiments.

Imagine two 10mm wide, little or zero divergence beams being kneif edged and sent down field with a 10% or say a 1mm, you pick, gap at the kneif. The near field is 21mm wide and the far field is 10mm or only the divergence larger because the beams can be adjusted to overlap at that point. If you are constrained to remain parallel ( don't know why) then the far field is 21mm pulse the divergence ( 1/2 angle x2 for each side). Now, if the two beams had each passed through the first stage of the zero power telescope to a "focus" of 1mm and then been knifed before collimnatimg back to 10 mm each would they have to diverge so severely by the time they reached this lens that they would grow to 21mm? I don't know, but I doubt it.

Alternatively, say there was no kneif edging and two diode/collimators sat side by side and projected their beams through identical telescopes which also sat side by side. In this case nothing overlaps in the near field, the scanner accommodates two adjacent,but non-overlapped beams and the far field is the overlapped, expanded beams. If the mechanical constraints on the mounts are removed and they are reduced in size arbitrarily then as they are slid closer and closer the two beams will begin to pass through just one telescope with at first wildly divergent down field paths, but eventually become parallel and co axial. The question is whether this becomes advantageous before the real life constraints of divergence, focus, emitter size interfere.

Don't think I am arguing with you. I have been around long enough to appreciate that your the one that has actually tried this while I have not. However, as I said to K above, can you get specific about your test conditions, lens FL, adjustment methods and spacings so that I dont't wast time re doing your experiments. Iwill also try to fine tune the tests to minimize the expense until there are some hard numbers to show success or failure. Thanks.

[mixedgas]

Jon,

Minimum FACing order, if you can get Blue Sky to even answer your phone, is ~200 pieces of diode, if they have already done the R&D for that model diode. Adds about 25-30$ to the cost of the raw diode.
I tried. They were not to interested in doing wide die diodes, either. Note that comes out FACed, computer tested, recanned, Quality assured, and the diodes have a special inert gas filling when done.

It took considerable persistence even to get them to talk to me. A mere hobbyist is not going to get past the secretary. I had to invoke the SEKRET magic words used by big contractors and use a corporate phone. Even then it took a week of trying.,

So all you "hobbyists" who want one piece FACed, forget calling em, it will just make it harder and harder to try to get them to talk.

Some 170 mW diodes we like, they stock FACed. However, still massive minimum order. Not even a LPF group buy could make the minimums.

I had access to funding when I called. It was not a "blind" call for one piece, which POs their sales organization to no end. Because of those annoying calls, their sales organization has no mercy for small quantity buyers.

Such is life.

Steve.

[p1t8ull]

Don't think I am arguing with you

Not at all. I'm not claiming this will never work, mine were basic tests and I didn't pursue the idea past a simple setup. The more the idea is bounced round, the more likely a positive outcome

can you get specific about your test conditions, lens FL, adjustment methods and spacings so that I dont't wast time re doing your experiments

I wish I could provide some accurate info, it was a long time ago (late 90's) when I tried this with a couple of low powered diodes - back then a high powered diode was capable of producing a massive 25mW and cost over £400 ($600)
I can remember that I tried both a zero magnification telescope and one with low (either 2 or 3) magnification, all PCX lenses that would have been around the 30-90mm FL range, and the results were very similar, if not identical iirc.
No accurate measurements were taken so I can't say of the higher mag telescope started to move things in a more positive direction or not, maybe that is key..

I can only say that at a basic level I didn't get any worthy results knifing in the small focal area between lenses, but with the skill and ability around here, if it can be worked out I'm sure it will be.

[dsli_jon]

..if you can get Blue Sky to even answer

Yeah, but doesn't anybody else out there, make a post-can FAC, offering similar majik? That < ) profile, like the ref-link in the 'FA/SA' thread.. I know their 'µLens' or whatver, is all patented out-the-peekaboo, etc, but.. we want a post-can solution, anyway... No existé?

j

[planters]

I am going to talk to the people at Doric Lens. They were helpful before.

[LaNeK779]

Yeah, but doesn't anybody else out there, make a post-can FAC, offering similar majik? That < ) profile, like the ref-link in the 'FA/SA' thread.. I know their 'µLens' or whatver, is all patented out-the-peekaboo, etc, but.. we want a post-can solution, anyway... No existé?

j

a workaround for this post can situation (a difficult one though) is to find the elusive 500mw mitsu diode, which is open can by default

[taggalucci]

a workaround for this post can situation (a difficult one though) is to find the elusive 500mw mitsu diode, which is open can by default

...or de-can the 300mWs

[steve-o]

...or de-can the 300mWs

Ohhhhhhhhohhhh

[kiyoukan]

They are not the exact same!
de canning a 300mw might get you more power but it is not the only difference between them.