Can it be true? 70W laser diode?

[nikola tesla]

Hey there,
I was inspired by another threat to look for the strongest laser diode I can find that a person can buy on the internet and I found THIS:
Osram 70W laserdiode

Now I tried to find more information about this but wasnt too sucessful.
After reading this pdf I still dont excactly know how this thing works and if its really 70W and if thats even possible in such a small scale.
What do you guys think?

 

[MarioMaster]

They're designed for high pulse power but operate on extremely low duty cycles so their average power output would be quite low. Think on the order of microseconds or less of on-time.

 

[Cenobite9]

Since it's in the IR band.... maybe....

 

[Cyparagon]

70W for what looks like a single 30ns pulse at an invisible wavelength in a huge 10x200 micron emitter area? Move along - nothing to see here.

 

[nikola tesla]

ahh ok so the pulses are way too short for the wattage to matter? (I thought maybe you could decide wether to pulse or not)
then I am curious about how strong the strongest laser diode is? i saw some with 10w that were definetely not pulsed but I heard there are even stronger diodes

 

[MarioMaster]

You could, but then the diode would toast itself before you could blink. Plastic package = no good for heat dissipation.

I personally own a 60W Coherent diode bar, it burns anything that absorbs short wave IR

 

[nikola tesla]

Oh ok. I thought maybe you could put the diode in a reaaly good heatsinking or active cooling system.. but that wouldnt be enough?

how does your diode bar work then?

 

[Bluefan]

If you really want insane powers from a diode:
Encyclopedia of Laser Physics and Technology - diode stacks, laser diodes, high-power lasers
Diode stacks are not even impressive in size, the typical width of a diode bar is 10mm. Stack a few of those and you have your diode stack. Kilowatt output power in a package a few centimeters big (not including cooling and power supply of course).

 

[nikola tesla]

but when the diodes are that close together dont they overheat in seconds?
wouldnt heatpipes be useful for cooling this? And if you need this massive cooling anyway, why not have one powerful diode in a really big heatsink?

 

[Bluefan]

The stacking density is limited by the cooling requirements, usually they are water cooled. Diodes don't scale very well in power. The limit is partially because of the limti in optical power per area that can pass throught he front facent. The front facent can't be made unlimited large, that why diode bars have 19 emitters in a row and diode stack ahve a number of those rows.

 

[nikola tesla]

sounds like these are extremely expensive

 

[MarioMaster]

Yeah as Bluefan said, usually these big diode bars are water cooled. I hook mine up to a small pump and water reservoir, then supply 3.5v at 75-90A (not mA) to the diode terminals.

 

[Ablaze]

A Laser to Give the Universe a Hernia? : Discovery News

 

[nikola tesla]

Interesting really. Wouldnt these stacks also be good for a cnc laser?

Is water cooling the only possibility? I thought If one cuts down on power or on the small scale then maybe heatpipes and a radiator with a fan could do the job.

@mariomaster: since I am now curious about how strong diodes can get: How much is the peak power of ONE of those bars you use, and how strong are the single diodes used in them? And how hot does one of these bars get? I mean are they like 100°C in a second or is the cooling for long term usage?

And still my question would be: how strong are the strongest single diodes that can be used without having to put them in liquid nitrogen?

 

[MarioMaster]

I don't know how many emitters there are in the bar, all the emitters are on one chip which are soldered inside the brick. The brick is designed for water cooling only. Lower powered diode bars that are not already packaged inside a unit could be air cooled.

They might be ok for a CNC cutter, but they have very poor beam quality, it would be difficult to get a precise cut. Plus a lot of common materials reflect like at the 800nm band where most of these high powered diode bars sit. The highest power in the style I have was 100W.

CO2 lasers are a much better match since they burn pretty much anything and can be focused much more easily.

 

[nikola tesla]

but arent diodes less energy hungry and smaller even in these bricks?
And dont Co2 lasers need even more cooling?