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

**andyf97** · 10-13-2011, 00:50

Some tests

Tested with a 3 lens barrel, quite interesting results, nice thin beam that looks correctable but looks like quite a bit of loss.

Tested with O-like & DRlava correction: results are interesting but not good enough and will end up costing too much.

Tested with G2 & DRlava correcton: Results not so amazing. G2 seams to be pointless but less losses.

Got out some prisms and put these with an o-like: Best results so far.

So what I think might work here but have to try it:

4 diodes knife edged together then after put onto a pair of prisms to correct the far field. I think this will give the best results with common lenses like an O-like and I have no idea what will happen to the 4 beams after the prisms, maybe they will be all over the place.

I will also try later some none conventional lenses because the results are close enough to warrant more testing and also test the losses with the 3 lens barrel as that had the best starting beam that looked more correctable with something like a beam expander.

My conclusion is if we can find the right first lens to get the initial beam small enough, its going to be very usable.

I tested at 38 meters and had a line around 40mm x 5mm with starting beam on the o-like clipped at around 4mm x 1mm

Didnt take any photos but might later when its dark enough to see better.

Forgot to add: The tests were done not very accurately with lenses almost thrown in front of the diode so am sure with proper rigging I will be able to get far better results.

**andyf97** · 10-13-2011, 05:11

Cracked it with, 2mm at the diode 12mm at 38meters. Will take some better photos later.

Attachment 28012

Used a little tiny lens which I don't know yet what its specs are I will have to look it up, then DrLava concave lens then a different one just after.

With a different first lens will be able to get the initial beam even smaller.

**planters** · 10-13-2011, 05:19

CDBEAM,
Your calculations look good. I have a prejudice however, when calculating divergence that will be applied to complex beams such as stacked arrays. I ignore the near field dimensions and simply divide the far field spot by the baseline as in 8.5mm/4,000mm = 2.12mrad. This is a small difference from your result and actually incorrect, but this is why. Imagine a stack of 6 of your 1.5mmx4mm lines as in llllll. The near field will be aprox. 9mm wide and if overlapped in the far field will be still aprox. 8.5mm in its largest dimension for a calculated divergence of near zero. Just another way of looking at this.

andyf97,
Your result with the O-like as in 40mm x 5mm at 40,000mm is aprox. 1mrad x 0.125mrad! Is this with only the O-like or is this with additional correction?

**CDBEAM** · 10-13-2011, 05:19

Yikes !!! MORE INFORMATION !!! Please. Can we nail the Red Holy Grail ???

Beam

Thanks Mr.P for your comments...I understand what you are saying......But I have a question.....If using the 137 calculator....Does one use the " Aperature profile ...at 0 feet "...Before or after the cylinderical lens pair ???? Anybody ???

**LaNeK779** · 10-13-2011, 05:26

Originally Posted by andyf97

Cracked it with, 2mm at the diode 12mm at 38meters. Will take some better photos later.
Used a little tiny lens which I don't know yet what its specs are I will have to look it up, then DrLava concave lens then a different one just after.
With a different first lens will be able to get the initial beam even smaller.

Is this tiny lens a FAC or GRIN lens? Whatever it is, it has to drop divergence very much, as by the looks of it the pcv and pcx cylinders are quite close to each other

can't wait for the better pics and beam shots.

can this really be it?????

**planters** · 10-13-2011, 05:28

When you say 2mm at the diode do you mean just after the last lens and therefore available for stacking? These results are 2-3 x better than the LOC diodes with similar near field dimensions. Are you SURE? And I assume you still have 4mm near and 5mm far field in the other axis?

**andyf97** · 10-13-2011, 05:29

Originally Posted by planters

Your result with the O-like as in 40mm x 5mm at 40,000mm is aprox. 1mrad x 0.125mrad! Is this with only the O-like or is this with additional correction?

With just the lens but after doing more tests I am wondering if the lens is actually an O-like because its quite good and better than say a G2.

**andyf97** · 10-13-2011, 05:30

Originally Posted by planters

When you say 2mm at the diode do you mean just after the last lens and therefore available for stacking? These results are 2-3 x better than the LOC diodes with similar near field dimensions. Are you SURE? And I assume you still have 4mm near and 5mm far field in the other axis?

I am very sure and will get it better. SO far as you can see on the photo my setup is a bit flimsy.

Update info to follow for PL members not balloon poppers.

**planters** · 10-13-2011, 05:48

CDBEAM,
With the same set up as andyf97 you got a larger near field 1.5mm x 4mm and a larger far field divergence at 2mrad. I'm confused.

Andyf97,
With your correction optics you expanded the near field 2x, but reduced your divergence nearly 4x. These results seem to good to be true. This is not a criticism, but a restrained EUREKA ! It seems to me that the only way this new second optic could possibly be so effective is if it were some type of complex aspheric, achromatic, GRIN ect. But even your results with just the O-like are fantastic as they exceed the colimnated 445 diode stripes prior to correction.

**planters** · 10-13-2011, 06:14

andyf97,
What are the dimensions of the beam just after the last optic?

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