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

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    Default 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
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    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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    Quote Originally Posted by CDBEAM View Post
    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
    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

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    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
    "its called character briggs..."

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    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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    Quote Originally Posted by flecom View Post
    I remember theres a reason why every time I think of that everyone tells me I'm an idiot lol
    i have the same vague recollection, i just need it thrown onto my face once again
    "its called character briggs..."

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    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
    Last edited by mixedgas; 09-28-2011 at 03:18.

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    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

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    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

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    Quote Originally Posted by mixedgas View Post
    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
    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!
    Last edited by absolom7691; 09-28-2011 at 06:45.

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    Quote Originally Posted by absolom7691 View Post
    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!
    wow, that is a much more politically correct way to express the same point my son expressed to me the other day: "Dad, you're the smartest guy I know. you've been thru almost everything, and learned all the lessons...
    That means your smart enough to understand that I won't actually care what you think, until I prove some shit to myself."

    I am happy to say, a rush to the hospital didn't closely follow that statement. Those could have been some good 'famous last words'

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    Well, I figure with innovation, no matter how futile, can be fun and educational. Not all of us have the optical knowledge that Steve and the others have, but we want to SEE why something won't work. There is that nagging thing in our heads that is telling us "I know this will work... I just know it". Curiosity killed the cat.......... and satisfaction brought him back!

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    Default Yikes !!! Lite Fuse and Run !!!

    MMM ??? The title sez it all....Lite Fuse and Run !!!...OK...The optics correction was ALL Terrawatts idea...
    As Curly would say..." Ima victum a Sorecomestance "

    Thanx for the posts....the quest goes on !!! If anyone does have a solution...PLEASE post...I will experiment myself....some.....just for educational reasons....and likely move on to the Opnext 637's

    cdbeam and TERRAWATT !!!
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    Last edited by CDBEAM; 09-28-2011 at 07:46. Reason: Typo
    Beam Axiom #1 ~The Quantum well is DEEP ! Photons for ALL !!
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    Beam Axiom #2 ~Yes...As a matter of fact...I DO wear tinfoil on my head !!
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    Beam Axiom #3 ~Whe'n dout...Po ah Donk awn et !!
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    Beam Axiom #4 ~A Chicken in every Pot, and a Laser Lumia in every Livingroom !!
    .
    Beam Axiom #5 ~"Abstract Photonic Expressionism"....is "Abstractonimical" !!
    .
    Beam Axiom #6 ~ "A Posse ad Essea" ~ From being possible to being actual ...is the beam target !

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    Dont care about PC. A year ago we were paying 1$ a mW for those diodes in onsies.

    At 70$, eh,,,, Go for it.

    I personally would save up for the opnext parts.

    Steve

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    Not gonna move on to the Opnext diodes, myself... price/mW is not worth it for me. I am going to play with this and see what I can do. I will most likely end up PBSing 2 of these and using a pinhole. I have a 350mW 640nm from Laserwave. If I can get 500mW out of this, then I would be happy. Pinholes after a prism pair actually do wonders. My 445 has a better beam than my Viasho green by using this exact method. dnar was the first to interest me into pinholing http://www.photonlexicon.com/forums/...c-prisms/page2

    I'll try this with these Mitsus and see how it looks.
    Last edited by absolom7691; 09-28-2011 at 13:52. Reason: spelling

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    On the subject of fiber, Karl (Laser Wizardry) wrote:
    (from another thread)

    if you are old school, try playing with fiber. 400 um fiber works great, fat beam, high losses, but close to TEM 00 out the end.
    He may have been referring to a single mode LD for a source, though.

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    I do agree that on scan mirrors smaller than 5mm these will not be so good on but.
    People who have mirrors around 6mm would be able to use these diodes with decent results.
    When stacking the beams i think the image in the OP means to stack them one on top of each other not next to.
    See image below
    beampattern.jpg
    I do agree there may be other ways but i think this thread is going to touch on alot unless one way works so well that we stop caring.
    Who knows we may be able to get the most power out of these by only using 1 prism on each diode and then combining 2 setups threw a pbs and just cut off the rest of the beam and not even bother trying to fold it.
    But for the sake of trial and error i would love to see every way someone can think of tested.

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    Default Photoxication !!!

    I still have a small amount of hope for these diodes. Experiments will be done, dead ends will be located,
    learning will happen....fun with optics....and frustration !! But Absol's point is that the Opnext 637 cost about $ 0.87/mW....and the ML520G71 cost about $ 0.14/mW....( assuming driving the Opnext to 200mW @ $ 175.00 @ and driving the ML520G71 to 500mW @ $ 70.00 @)
    My goal is to acheive 2W of 635/637nm after optics for Projector #2. Huge $$$ difference depending on optics loss between the two LD's......ARGHHHHHH !! The injustice !! I will experiment with a 405-G-1 and DrLava Cylinderical lenses....and see what pops outa the other end !! Just a note....the last idea is ALSO from Terrawatt !!! haha

    CDBEAM
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    Beam Axiom #1 ~The Quantum well is DEEP ! Photons for ALL !!
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    Beam Axiom #2 ~Yes...As a matter of fact...I DO wear tinfoil on my head !!
    .
    Beam Axiom #3 ~Whe'n dout...Po ah Donk awn et !!
    .
    Beam Axiom #4 ~A Chicken in every Pot, and a Laser Lumia in every Livingroom !!
    .
    Beam Axiom #5 ~"Abstract Photonic Expressionism"....is "Abstractonimical" !!
    .
    Beam Axiom #6 ~ "A Posse ad Essea" ~ From being possible to being actual ...is the beam target !

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    Quote Originally Posted by CDBEAM View Post
    will experiment with a 405-G-1 and DrLava Cylinderical lenses....and see what pops outa the other end !!
    toss the blue lens, use an optima red lens, slightly shorter FL, should work even better with cylinders
    "its called character briggs..."

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    OK....But I gotta get the Optima Red....Lets see what the 405-G-1 does....anyone else have the ML520G71 + OptimaRed + Lavas lenses ??? mmmm ??? Gopher it !!!!

    CDBEAM
    Beam Axiom #1 ~The Quantum well is DEEP ! Photons for ALL !!
    .
    Beam Axiom #2 ~Yes...As a matter of fact...I DO wear tinfoil on my head !!
    .
    Beam Axiom #3 ~Whe'n dout...Po ah Donk awn et !!
    .
    Beam Axiom #4 ~A Chicken in every Pot, and a Laser Lumia in every Livingroom !!
    .
    Beam Axiom #5 ~"Abstract Photonic Expressionism"....is "Abstractonimical" !!
    .
    Beam Axiom #6 ~ "A Posse ad Essea" ~ From being possible to being actual ...is the beam target !

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    I think that is where possibly some are saying that these are not usable. I am just after 500mW, corrected to fit on some 3mm mirrors. I don't care if I lose 75% in all the optics (collimaters, prisms, wave plates, PBS and pinhole). If I need 2W to manipulate it down to a usable beam and get 500mW, I would be fine with this. The price of these will still be cheaper. These have also been overdriven by a lot and hold up well. Of course, overdriving them will shorten the lifespan, but if you only get 2500 hours out of them that is still a lot of time (unless you do gigs every night). I use my projector in the garage so, not a lot of use. I just want something to go with my 300mW green and my corrected 445, which after optics, is about 600mW. My LW 640nm is not able to keep up without attenuating the blue a little and the green a lot. 500mW of 635 would look mighty sweet.

    I do see, however, Steve's point here. When you start stacking beams and try to get multi-watts out of them, you are going to get a shit beam. Stacking too many diodes is pointless if you are going to pinhole. It may be possible to run a quad, knife edge the pairs tightly and combine them in the same orientation via wave plate and PBS, correct them via prism and then pinhole with a slightly larger diameter aperature (say 4mm), this is what I have in mind for my setup. Beyond that, kinfe edging a quad, or knife edging two groups of 3 or more and PBSing them... now the pinhole idea will start cutting off the additional beams and would be the same effect of trying to make a sailboat move by aiming a large fan at the sail from inside the boat. So yes, I can see where Steve is coming from. 2W of graphics capable red... I think we would seriously need Indiana Jones and his dad to help us find that grail.

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    Quote Originally Posted by absolom7691 View Post
    When you start stacking beams and try to get multi-watts out of them, you are going to get a shit beam.
    thing is even if you stack a bunch of the opnext diodes you still get a shit beam... or you have high power 650 red diodes, shit beam...

    if you want a lot of red for cheap you need to come to terms with giant beams... get bigger scanner mirrors or go home

    anyway I would not want a 1W red with a LOC type beam, think of the power density! would be pretty dangerous

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    I hear ya. I am itching for my weekend to start so I can play with the ones I just got. Honestly, as has been said before, it seems like the public doesn't care if beams are too big. So, there you have it.

    Can you guys stop being so selfish. One of you needs to stop what you are doing, go to school and get a phD in optical and chemical engineering. Then, you can find us better lasing mediums!

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    Quote Originally Posted by absolom7691 View Post
    I hear ya. I am itching for my weekend to start so I can play with the ones I just got. Honestly, as has been said before, it seems like the public doesn't care if beams are too big. So, there you have it.
    I find it amusing that on one end we have the people with the endless quest for tiny HeNe like beams, then on the other end we have people developing lenses to diverge your output for safety... umm... so if we are going to diverge it who cares if the beam is big to begin with?

    we can just get bigger scanner mirrors and diverge the other colors to match

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    I love the enthusiasm in this thread, it's infectious and I hope you guys come up with something workable.

    Quote Originally Posted by CDBEAM View Post
    But Absol's point is that the Opnext 637 cost about $ 0.87/mW....and the ML520G71 cost about $ 0.14/mW....( assuming driving the Opnext to 200mW @ $ 175.00 @ and driving the ML520G71 to 500mW @ $ 70.00 @)
    I'm not sure I agree with your maths.

    mW/$ comparisons should be calculated post optics losses and should factor in power density and divergence. I would be interested to see if there's an equation demonstrating same or better (preferably) power density and divergence from these Mitsubishi diodes compared to their OpNext cousins.

    I suspect the cost of the holy grail of optics to produce an ideal beam from the Mitsubishi diodes would be more than the cost of getting an equivalent beam using the OpNexts.

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