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

I thought I would start a new post for the ML520G71 corrective optics speculations. Please see the attached drawing. This concept is based on the ideas from LaNek779, Kiyoukan, Steve-O, Planters, Mixedgas, and p1t8ull. There is nothing really new here...BUT..." It could work ". An inexpensive Red at the 638 line....would be fine !!! Two LD's going thru aspherical lenses...then, into knife edges to split the beam in half and feed it back into itself via the waveplate and PBS. Then knife edge those to combine them....and finally shoot thru telescope optics to tighten things up !!! This MIGHT work for beam shows ?
Your thoughts ???? Thanx !

CDBEAM

Reposting what I asked over in the DTR's thread:

I can get my hands on some 3mm fiber. Is it not possible to focus the beam down and at the focal point, inject the light into the fiber, at the other end, collimate the output from the fiber? Please correct me if I am wrong, but would this not give you a near TEM00 beam??

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Originally Posted by CDBEAM

I thought I would start a new post for the ML520G71 corrective optics speculations. Please see the attached drawing. This concept is based on the ideas from LaNek779, Kiyoukan, Steve-O, Planters, Mixedgas, and p1t8ull. There is nothing really new here...BUT..." It could work ". An inexpensive Red at the 638 line....would be fine !!! Two LD's going thru aspherical lenses...then, into knife edges to split the beam in half and feed it back into itself via the waveplate and PBS. Then knife edge those to combine them....and finally shoot thru telescope optics to tighten things up !!! This MIGHT work for beam shows ?
Your thoughts ???? Thanx !

CDBEAM

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I'm not seeing the point in that... your making both beams half as big to then knife edge them making them just as big as you started... you could just PBS two beams and have a similar result I think

First of all, thanks for the compliment CDBEAM, listing me up there along with the "titans" of optics, but i actually had no original idea, just linked to a thread with interesting ideas, especially one by loopee that i particularly liked.


concerning your design if i may post a few comments,

first of all, these diodes start of with a divergence of more than 3mrad, so beam correction should take place before anything else happens
then, if we fold the beams independently and then knife edge them together (the main knifeedge in your design) we end up with another fat beam, so we lose the benefits from the beam folding
finally, i can't see the need for the 3:1 telescope, as this will also triple divergence back (or even more) to the original uncorrected raw beam


maybe it would be better if the setup was like:
beam correction with prisms on each diode independently, then knife edging the two corrected beams together and then using the knife edge mirror and two bounce mirrors, waveplate + pbs to fold the beam, discarding the telescope.


@ absolom: i wish i could enlighten you in terms of launching in fibers, but i have no idea whatseover...


i was thinking (in terms of a blue red satelite projector only) to get divergence to an acceptable 1.5, disregarding beam size, then combine it with a fat beam coming from two 445s and then using a 1:1 ratio telescope (before and after the galvos) to compress the beam for a short length, fit it on the scannets and get it back to normal again. i can' t seem to fit the green in this mix yet that's why i say red-blue only

I think the problem with telescopes after the scanners is when the scanners hit the lens at different angles you get some pretty nasty image distortion... or something like that...

I remember theres a reason why every time I think of that everyone tells me I'm an idiot lol

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Originally Posted by flecom

I remember theres a reason why every time I think of that everyone tells me I'm an idiot lol

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i have the same vague recollection, i just need it thrown onto my face once again :) :) :) :) :) :)

How many times do we have to go through this? ARGHHHHHHH!!!!!!

I regret ever posting about this diode!

I'm under a NDA, so I can't show you pictures. Some one else paid for that attempt. Do NOT waste your time with this one unless you want a short range lumia or a beam that just fits oversized galvos. It is designed to feed a video integrator, which is a kalideoscope of sorts. With a F1 lens in front of it, your down 33% or more right off the bat due to collection angle.

THAT horizontal number is FULL WIDTH HALF MAXIMUM, but the distribution is NOT tem00.

Four really good PLers have had this one on the bench, and we all came to the same conclusion.


Combine two other 635 nm diodes.


Steve

so where can I get two 635 diodes that will give me 1W for $70?

again, I think the costs demand a solution, same as the 445 diodes... they were "not suitable" for projector use... now quite literally everyone has them in their projector... 473 is becoming a novelty... the price/mW says that a solution, even if expensive or not ideal, is still a solution worth trying...

if I can get them to make a beam at least the same size as the 650 flashlights I will be quite pleased

To fit the beam on 3mm mirrors I think the price for correction optics and power loss outweighs the cheap price. Better off with the opnext 638 small emitter diodes. Only need one lens for them.

If you can tolerate 5mm plus mirrors then these diodes can be made to work. Especially if you are trying to match the 445 diode far field spot.

This is what I have measured. Hopefully someone can prove me wrong and come up with a better correction method:D

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Originally Posted by mixedgas

How many times do we have to go through this? ARGHHHHHHH!!!!!!

I regret ever posting about this diode!

I'm under a NDA, so I can't show you pictures. Some one else paid for that attempt. Do NOT waste your time with this one unless you want a short range lumia or a beam that just fits oversized galvos. It is designed to feed a video integrator, which is a kalideoscope of sorts. With a F1 lens in front of it, your down 33% or more right off the bat due to collection angle.

THAT horizontal number is FULL WIDTH HALF MAXIMUM, but the distribution is NOT tem00.

Four really good PLers have had this one on the bench, and we all came to the same conclusion.


Combine two other 635 nm diodes.


Steve

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Steve, I have the utmost respect for you and the knowledge you bring to this forum. Like with chess players, you are a Grandmaster in this field, one of many and you seem very eager to help us learn. However, sometimes you seem to forget that experience is teaching too. $70 is not that much for most of us here. If it were, we are in the wrong hobby. 80% of us probably have spare optics lying around, along with diode mounts, flexmods, TECs, wire, solder, frozen box of Thin Mints that we are hording until the Girl Scouts come around again next year etc etc etc. All I am saying is, this is a pretty cheap experiment. If it can't be done, it can't be done. We will learn why it can't be done. Yes, some of us have to stick our hand in the fire to realize that we will get burned. I really appreciate your concern for our pocketbooks but this is not a $500 635nm C-mount... $70, I will play with this for $70. I may come out with a 500mW red for my lumia. I know you said others have tried this before. Sometimes it takes someone else working it in a way that escaped other people. Let us hold back a night out with the guys, knocking back some brews at the bar and instead spend it on some cheap red. When stuff like this comes up, that is when I have fun. I like trying to figure something out. Steve, again, you rock... but ease up a bit! :)