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Worst Diode Ever lol (PIX)

ouch3994

ouch3994

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Jan 19, 2011
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I recently purchased a 445nm diode from Survival Lasers. It was packaged very securely, but I am pretty sure i got one of the most inefficient 445nm diodes evvvver ^_^
I was very careful with installing this into my C6 host, for i know the dangers of static... but I am positive I just have a terrible diode :( 48$ wasted

I am running this with a moh's linear driver @1.25A

The beam looks as though there are two parallel laser beams
When focused to a small point, this laser barely burns. My 250mw Lpc-826 laser burns with more power.

I have just recieved a new diode from DTR (fantastic, quick service btw :D) that i will replace this one, I will be replacing it this week and I am not sure whether or not to keep this dud-diode...

Any thoughts of what could be wrong with the diode? :thinking:


Raw output:
photo21-1.jpg



405 glass lens:
photo1-1.jpg


DOUBLE BEAMSHHOTTT:
photo41-1.jpg


normal focus:
photo31-1.jpg
 
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That looks not good. Try other currents. The beam patrons changes with the current.
 
This happens on occasion sorry to hear of your loss, BTW it's a good reason to buy a "TESTED" diode they are only $2.00 more than you payed
for that one and you know EXACTLY what you are getting as you will get the spec's from the test.

I just got a diode like yours and it came from the same source a M-140 projector.

It preforms pretty much like yours right out of the projector, it has an out put of 123mW with a input current of 1100ma and it dose get hot fast.

I have this bagged diode here as a reference diode in case people don't believe they come from the projector like this. I also have a couple
completely dead diodes straight out of a M-140 and a A-140 projector.
 
Not dead, not alive, somewhere in between. This is what we call a zombie diode.
 
Never seen that pattern before. I thought the facets run vertical. Or is that just 2 facets?
 
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Here goes, trying to apply macrophysical logic to quantum devices. Eh, what harm could it do? My guess is that the middle of the facet is broken, probably too much power through it, and the outer area of the facet is still in good condition, allowing the light to be reflected back into the laser cavity and amplified in the outer parts of the diode.

I like to think of diodes' similarities with classical lasers. They are very much alike, only made differently and smaller. Since the cavity is so short, divergence is pretty bad.
Also, gain medium isn't a gas, but a semiconductor.
And the mirrors are not seperate, but formed by cleaving the semiconductor crystal. Since a weak plane in the crystal lattice, it snaps nice and flat, kind of like when you are cutting glass, except more precise because of the structure of the material.

I imagine if you took a HeNe and scratched the hell out of the center of the output mirror (synonymous in this example with the front facet of your diode) without harming the entire beam cross section, you would probably get a dark spot in the middle of the beam, and relatively normal performance where the mirror wasn't damaged.
 
You get bad diodes from time to time. Nothing you can do about it.

No matter who you buy from you can still get a inefficient diode.

Ive bought diodes from members before as well as extracted many projectors myself and i can tell you that it happens. There is no one to blame on our level.

No one will guaranty a diode once it leaves there hands.! Even if it is tested.

Also as a side note Every diode that i ever bought from SL was efficient. I have extracted projectors and found in a couple of them up to 4 inefficient diodes in there.

You never know what your going to get.

Put it this way you have the same chance of getting a In efficient diode from member X as you do with Y or Z.


There are other factors towards a diode being damage then being really careful as you say with ESD.

Over heating the diode with your soldering iron is also possible. Not discharging the caps on your driver is another way to damage a diode.
 
I was going to say the main line looks blown on that diode and the outer lines are still lasing. Could be ESD or a spike from a capacitor or it could have been bad right out of the projector. You do find duds in the arrays from time to time.;)
 
Tested diodes don't guarantee good results, unfortunately. There are a lot of other factors involved as Lazeerer said.

PM sent.
 
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That diode is actually kind of neat, the way the two beams are parallel to eachother...
 
Garoq said:
Tested diodes don't necessarily guarantee good results...I'll post a link from another thread later when I can get on my laptop. Ouch3994, I don't want you to feel like you wasted your money with SL, I will send you a PM.
Click to expand...

I'm sorry if the wording of my original post implies that i "wasted my money" using Survival Lasers, I certainly did not mean it in that way. I simply wanted to show the unique "parallel beam" effect I was getting with the diode, and I definitely will continue to purchase pieces from SL. I am still in school and I have nothing else to spend my work money on, so I don't feel like I have wasted money. :yabbem:
I am soon to begin experimenting with the high-powered 405nm diodes, so you can expect to see some purchases from me within a month ;)
 
I also happen to know a Nigerian prince who can wire you some money after a bank deposit...


Seems pretty legit, perhaps good for some extra money? :whistle:
 
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