Old 06-21-2008, 11:06 PM #17
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Default Re: laser overdriven?

What do you mean by "work well without dieing"? How do Meredith module and heatsink fit into this question?

A diode won't die unless you drive it too hard.. There is a certain current you should not go over. You also should not let it get too hot.. The bigger heatsink you have, the longer you can leave it on - because the heat dissipates into the mass of the heatsink.

A Meredith glass lens will allow you to reach the highest power. You get 20% more power, compared to a Meredith acrylic (AR coated for reds). Even more than 20% compared to AixiZ acrylic, which are clear (AR coatings reduce reflective losses, an AixiZ acrylic has no coating).

The Meredith heatsink is a block of brass.. It should allow operation for a very long time.. 16x diodes do not dissipate that much heat. They are more efficient, but die at a lower current, than an open can. (a higher power diode requires a higher current for the same power - lower efficiency - but it can reach a higher power)....


So it's not about the module and the heatsink. Any module and heatsink will work for the 16x SenKat diode.. You need to worry about what current to drive it at.

I heard the last batch can survive up to 400mA, but there is not much but heat coming out from 350mA up... So 330-340mA should be optimal for the most power and longevity.


It would give you around 200mW after a clear acrylic lens... A few mW more with a 650nm AR coated acrylic lens. And around 240mW after a Meredith glass lens.. Could be a bit more. Haven't tested them myself yet.


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Old 06-21-2008, 11:38 PM #18
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Default Re: laser overdriven?

Quote:
Originally Posted by styropyro
[quote author=IgorT link=1214033864/0#10 date=1214065008]and you're not really getting much more power from all that extra current.
Shouldn't he get a decent amount more power at that current? Gazoo got over 400mW out of an open can at 570mA. Gazoo was using a Merideth glass lens though.[/quote]

You would think that more current will make it brighter, but my variable red looks brighter at 300 ma's then it does at 350. Also at 350 there is that stupid line going through the beam. :P
I do think that the wavelength can change though.

--hydro15
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Old 06-21-2008, 11:52 PM #19
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Default Re: laser overdriven?

Yes, the wavelength can change.. It changes with heat. It goes up. And if you cool a diode, it goes down. Some people try to noticeably change it, by freezing.. And with IR pump diodes in green lasers, if the wavelength changes too much from heat, it can reduce the conversion efficiency of the crystal - there is a very narrow range where the conversion is efficient. It's the same with all diodes.

But with reds, there is not that much visible difference between 200 and 250mW anyway.


You get a line only at 350mA? What diode is this? SenKat's new 16x?
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Old 06-22-2008, 12:00 AM #20
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Default Re: laser overdriven?

Quote:
Originally Posted by IgorT
What do you mean by "work well without dieing"? How do Meredith module and heatsink fit into this question?

A diode won't die unless you drive it too hard.. There is a certain current you should not go over. You also should not let it get too hot.. The bigger heatsink you have, the longer you can leave it on - because the heat dissipates into the mass of the heatsink.

A Meredith glass lens will allow you to reach the highest power. You get 20% more power, compared to a Meredith acrylic (AR coated for reds). Even more than 20% compared to AixiZ acrylic, which are clear (AR coatings reduce reflective losses, an AixiZ acrylic has no coating).

The Meredith heatsink is a block of brass.. It should allow operation for a very long time.. 16x diodes do not dissipate that much heat. They are more efficient, but die at a lower current, than an open can. (a higher power diode requires a higher current for the same power - lower efficiency - but it can reach a higher power)....


So it's not about the module and the heatsink. Any module and heatsink will work for the 16x SenKat diode.. You need to worry about what current to drive it at.

I heard the last batch can survive up to 400mA, but there is not much but heat coming out from 350mA up... So 330-340mA should be optimal for the most power and longevity.


It would give you around 200mW after a clear acrylic lens... A few mW more with a 650nm AR coated acrylic lens. And around 240mW after a Meredith glass lens.. Could be a bit more. Haven't tested them myself yet.
sorry I forgot to add 400ma...
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Old 06-22-2008, 12:13 AM #21
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Default Re: laser overdriven?

Well, as i mentioned before.. After 350mA, you're only increasing the heat in that diode.

There is absolutely no point in doing that. The power can actually go down. You should be happy, that the new batch of SenKat's diodes can survive that much current. That means it won't just die when you run it at 350mA.

Give it a good heatsink and optics, and it'll give you 250mW or maybe even a bit more with the Meredith glass lens.

Even if the power would increase by a few mW after 350mA, you would not see the difference in brightness, you would not see it in burning power - all you would be doing is risking the diode for nothing.


If you want to reach 300mW, you need an open can and a Meredith glass, i'm afraid.
The new 16x diode should make a nice 200-250mW laser, depending on optics.
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