DTR's Laser Shop: Diodes-Drivers-Lenses-LEDs & More

[Stiffler]

Does this mean that this diode does come with a FAC lens attached ?

Yes, he mentioned it in a previous post. Can someone please explain to me what a FAC does, and if it is desirable??

[VDX]

... AFAIK it's often used for "Fast-Axis-Collimator" what's mostly a cylinder lens, that converges the 'fast axis' of the emitter, that outputs with higer divergence, so the resulting beam would be more homogene.

But sometimes I found FAC as reference for "Fiber-Array-Coupler", where a diode-array with more emitters in one wide stripe is connected with glass fibers, that feeds the light from the emitters to a combined bundle - have a Coherent diode with an 'output' where 19 fibers with 105µm each are combined to a bundle of maybe 0.8mm ...

Viktor

[Lazeerer]

Thanks for that Lazeerer. That clarifies things a bit. I probably stirred the pot a bit with my "its top sekret" comment. Sorry about that. I do that kinda stuff here too and on other forums as well. No bad intentions meant at all.
So, more of these are still being built? That's good. No data sheet though.. that's strange .. hmm. They're $300+ something bucks each? Not too bad for that kind of power. Any idea of the wavelength? Maybe you posted it and I missed it. Do you think the price will go down eventually, or being a custom job probably not.
Have a good one and thanks..
PS- the only optics advice I can think of is try to measure the emitter and obtain the raw beam divergence. We may be able to collectively figure out a "grail" solution for ya

No Worries my Friend. Just trying to help out and hopefully get others to enjoy this diode. No need to apologies.


Yes they are being made. I guess probably for Replacements. Yeah iam sure there is the Work Order/data sheet but its not available to me. Any diodes i have ever gotten like this i rarely see a data sheet with them. Not sure if he can show them to me either. They are ~$400 and i can honestly say the price will not go down. These are as i was told $5000 diodes. Iam sure cheaper in there order but none the less they are expensive little guys. But if you think about it lets say even at ~3.5W-4W a diode after optics etc if you where attempting to build such a powerful "Red" laser in a array setup it would cost well over double that including the multiple diodes needed,Optics,optic mounts and mostly a lot more work and take up alot of space. Iam guessing here but i would think a 3-4W red array module that someone would put together would cost up in the near 1K+ dollars probably more.

So they are indeed prices but if you think about it they are kinda not due to the power like you mentioned.


The FAC comes already pre attached to the diode.


For Wavelength they are 650nm. I was going to make this long video in my TEC module setup showing everything but i popped the diode on purpose to see where they die at. Here was the video:


http://www.youtube.com/watch?v=bUmnCqxpVTY




So i dint get the chance to retest if the wavelength drops more but i just did a simple test next to a know 660nm laser and it for sure 10nm or so apart. Since i have a couple more diodes now i can retest that for you guys and see if i can get the WL to drop.


I dont have a microscope to measure the emitter however a diode i sold to someone does have one and i can ask him to measure it. My guess is that is ~200uM or possible larger.. I can though measure the raw divergence so ill get those numbers tonight.

I also posted some pictures of different 650 diodes i have and tested with a little information on them.

Here was the post maybe it will be interesting:

In the Picture bellow from left to right is:

500mW - 1000mW - These diodes
All diodes have a FAC lens







500mW 650nm C-Mount Vs this diode:



1W 650nm C-Mount VS this diode:



As you can see No comparison to cheap reproductions.

Some might not know but in china they do make alot of Knock off laser diodes. There is nothing wrong with that and most of the time they function just fine but are UN reliable. I bought 6 of the 500mW 650nm diodes. Spec sheet said MAX 1.5A and 4 popped before 1.1A However when chilled this diodes where able to hit ~ 800mW-1W OK However man the beam is Ugly. Its much larger then the diodes i show in this thread. I keeped the other 2 to use.

Same for the 1W diode. I was surprise to see that the 500mW has 6 bond wire and the 1W has only 3. But the die is bigger so yeah. Beam is a little worse then the 500mW diode. The Max Currant for the 1W was 1.5A Oswell. So yea dint sound right.

One big issue i found was the FAC where terrible The size of the FAC was not properly matched to the size of the die.

I remember this was extremely important when talking with the guy that did our Mitsubishi G71 638nm diodes. He first put on a Thin "For simple terms" FAC and it was Not correcting the beam that well and then moved to a thicker one and made a big difference.

Whatever FAC is put on these 5W 650nm diodes is dead perfect for the die. I cant believe the beam next to the 500mW 650nm diode.

Anyway, Just wanted to show the big difference in the die quality and the overall diode.

PLEASE NOTE: Iam sure there is more then just these 2 500mW and 1W 650nm diodes available but these where purchase from ebay and china sellers so pretty much this is what you see floating around but not limited to just this.

Let me know if anyone wants me to try anything.

[badger1666]

Would be nice to see what happens with a set of cylinder lenses and one of these diodes

[polishedball]

Think DTR set it up like that

Would be nice to see what happens with a set of cylinder lenses and one of these diodes

[steve-o]

I would hazard a guess that a beam expander may help keep the divergence down , I don't know if cylinder lenses used in conjunction with a fast axis collimation lens (already built in) would do a lot of good or not.
Wow dude, popping a $400 diode just to see when it'll pop?? That's -- uh -- expensive ..

[Stiffler]

^^ Yeah, what was the output at 7 amps?

[steve-o]

Yes, he mentioned it in a previous post. Can someone please explain to me what a FAC does, and if it is desirable??

Yes it means that you need less optics (& less pain in the arse) because the fast axis (the most divergent part of the beam) is now under control and similar in properties to the slow axis, making beam correction/ collimation simpler, possibly requiring only one collimating lens instead of having to fool with correction optics such as prisms etc. Yeah it's a real good thing.

--edit-- typing same time you were stiffler ..
Yeh I'd be curious about the curve plot too .. current vs output ..

[Stiffler]

I am curious what these diodes were intended for, they are BEASTS!! Pumping something perhaps??

[badger1666]

Steve i was thinking of the cylinder lens on the slow axis and then a focusing lens
To finish it off , this should give a nice spot to start with instead of the
Thin line that there is in the pics at the moment

I would hazard a guess that a beam expander may help keep the divergence down , I don't know if cylinder lenses used in conjunction with a fast axis collimation lens (already built in) would do a lot of good or not.
Wow dude, popping a $400 diode just to see when it'll pop?? That's -- uh -- expensive ..