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Thread: 445nm diode info

  1. #11
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    If you are reading this it means that this post used to contain some sort of helpful/educational information posted by me. I no longer have even the tiniest interest in contributing ANY knowledge or effort here on photonlexicon.com. Why should anyone here benefit from my hard work? It's not like there's even the tiniest bit of appreciation coming my way from those people whom I've tried to help since I've been here, both by plugging their products and by consolidating info.

    I apologize for not being able to help here anymore. If you want someone to thank for turning me against the idea of lending my hand to this particular community, thank our member dsli_jon for demonstrating quite convincingly SEVERAL times just what a smug, superior and condescending bunch of douchebags some of the so-called "professional laserists" here can be to people who think or act differently than they do. You can gold plate a piece of shit by calling it "professional", but at the end of the day it's still just a piece of shit. It only takes one worthless individual to screw up the public image of a whole group, at least in my book. "Professional" my ass.

    To any and all new members who might someday read this: NEVER let dsli_jon or any of the so-called "professionals" here talk to you in any way that you find to be rude, smug, snobbish, condescending or disrespectful because people like dsli_jon don't know how to speak any other way. The concept of "respecting others and their opinions/viewpoints" is entirely lost on him and people like him. All that matters is that they somehow have an opportunity to display their superiority complexes for all the world to see.

    The really sad part of all this: Who knows how many worthwhile future contributors and quality individuals have been run out of here by some of the absolutely ridiculous, "high-school-esque" bad attitudes that many members here like Jon have given people who might ask n00bish questions or who might bring up topics that they feel shouldn't be discussed here. To me it's very sad that people as absolutely worthless as Jon and his supporters have any sort of influence here. If you're a new member who is not prepared to bend over and take whatever these people give you, you'd better just leave now because they have zero tolerance for "thinking outside their box".
    Last edited by ElektroFreak; 08-23-2010 at 09:02.

  2. #12
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    Quote Originally Posted by ElektroFreak View Post
    Personal experience with blu-rays, hand on trial and error. Nothing scientific really.. I was building some modules over one winter using PHR diodes. I was working in a very dry area and static was ridiculous. I must have killed 6-8 modules very early on in their lives just by randomly or accidentally touching the housing I had them installed in. After examining everything, I decided to try connecting the case pin to the cathode. I haven't killed a single blu-ray diode since, static or otherwise. The rest of that winter and another have passed since then, and I still work in a dry static-prone area. I do have safeguards around my electronics work area, but it was always during normal usage elsewhere in my shop that static sparks would form.
    The cathode is (in principle, if my semiconductor theory is still fresh enough) connected to the diode's substrate, so that would make perfect sense.

    Why some manufacturers connect the anode to the case is a mystery, since the cathode surface (and substrate) is a lot larger and would make the diode more EMC and ESD resistant.

  3. #13
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    A link to the webpage I am working on for the data I have collected, http://www.krazerlasers.com/lasers/445nm/

    So far its pretty slim, mainly because I am in the midst of finals week at school, but I hope to grow it. If anyone has information, better pictures, etc, you would like me to add please post in this thread with a note giving me permission to host it.

    One note-so far I have tried to not put enough information to give away how to get a hold of one of the projectors, the point is not how to get a hold of the diodes but rather to educate about them. I am open to adding more complete information, since honestly trying to hide it is not going to work...

    Also-- if someone can provide scope captures of the projector in normal vs economy mode (doesn't need to be current, voltage across the diodes is fine) I need to confirm what the duty cycle is in normal mode. It looks like these diodes are being run at 2.2W during the 'on' time!

    edit - Please check this page again, I have added a large amount of info (including some long term testing), and realized that I made a computational error in the initial power calculations. The diode peaks at 1.7W in the projector, not 2.25 as I had previously estimated.
    Last edited by krazer; 06-20-2010 at 12:53. Reason: measurement error

  4. #14
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    Quote Originally Posted by krazer View Post
    Sorry to post spam, but with the amount of thread duplication going on I think its justified to post another link to the webpage I am working on for the data I have collected, http://www.krazerlasers.com/lasers/445nm/
    Interesting page! Cool you did a spectrum analysis. So the diodes aren't 445nm at all.. they're 443nm

  5. #15
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    stoney:
    from what I heard, "our" case-negative or freefloating diodes are the exception. the emitting spot, quantum well, resonator, whatever you call it, is very close to the anode side of the die. maybe around 1% from the anode side and 99% from the cathode side (remember the lasing area can be as small as a bacteria). so temperature-wise it makes perfect sense to "turn it around", so the generated heat doesnt have to travel through the slim emitter, but is directly at the large mount-surface.

    I cant insert images (nor anything else!), have a look here:
    http://www.die4laser.com/Image7.jpg
    http://www.die4laser.com/Image8.jpg
    from robin's http://www.die4laser.com/ site, shows the upper and lower side of a larger die.

    manuel

  6. #16
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    Vf:4.4V
    If:1.03A

    Vthresh:3.6V
    Ithresh:200mA

  7. #17
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    Quote Originally Posted by krazer View Post
    Also-- if someone can provide scope captures of the projector in normal vs economy mode (doesn't need to be current, voltage across the diodes is fine) I need to confirm what the duty cycle is in normal mode. It looks like these diodes are being run at 2.2W during the 'on' time!
    Like, eek.

    That would mean they could do 1,25-1,5W CW with proper cooling.

    Quad it up and you got a monster that would knock most argons out of the sky.

  8. #18
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    Quote Originally Posted by SideFX View Post
    Interesting page! Cool you did a spectrum analysis. So the diodes aren't 445nm at all.. they're 443nm
    I was doing a spectral analysis as well and found for the first diode I checked that it runs single longitudinal mode up to 55mW - which is stunning, and good news for holographers! I plan to perform over time a more detailed analysis, incl ECDL setups, and present the results here: http://hololaser.wordpress.com.

  9. #19
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    I was actually wondering it is was possible to get these diodes running singlemode, I have a process instruments 'wavelength narrowed' 650nm ECDL laser that has a highly multi mode diode that is stabilized with a grating and is supposed to have a 1GHz linewidth (in actuality its running multimode ) so it should at least be possible. Sadly all of my spectrum measuring devices are going to be in the wrong county for the next few weeks, but hopefully later in the summer I can contribute some meaningful information. In the mean time it just a link to you guys

  10. #20
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    Quote Originally Posted by RedlumX View Post
    I was doing a spectral analysis as well and found for the first diode I checked that it runs single longitudinal mode up to 55mW - which is stunning, and good news for holographers! I plan to perform over time a more detailed analysis, incl ECDL setups, and present the results here: http://hololaser.wordpress.com.
    absolutely amazing! so we can have singlemode output or amazing multimode-power? best news today, thank you a ton! :-)

    would love to see a vid of the raw output when slowly ramping up the current..

    Manuel

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