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Sharp 505nm

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Sounds good, Singlemode. I ordered four of these diodes not long after you did, so maybe the ones I ordered will get to me soon. I know we are not in the same hemisphere. Not even close, but I am optimistic. :yh:

Tracked Shipping from us to Germany is sbout 12$. Not a lot if multiple diodes are send together.

Singlemode
 

paul1598419

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Tracked shipping to me is free. I'm on the west coast so I do get things from China pretty quickly. Usually 10 to 15 days.
 
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So, my temperature stabilized setup is all set up, and the first 503nm diode is in the mount, collimated and coupled into a multi-mode fibre, I use an optical spectrum analyzer for central WL and spectrum analysis and can already say, that the internal modes are much more far away that for the 450nm diodes. I hope to spectro all the 7 diodes I have right now in the moment and measure the temperature and current WL/tuning coefficient of one of them (will be the same for the remaining diodes anyway). If the yield of < 502nm diodes is high enough, I will order another run of these diodes from newgazer, since exotherm increased his prices up to 100$ (thought they were the same seller anyway).

Singlemode
 

paul1598419

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I am still waiting on the diodes I ordered. I am very interested in your results as i have nothing to test at the moment. I was able to send Techhood a message and offered $30.00 each for mine. They were accepted, so you might want to go this route when you reorder.
 
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So, here are the WL results of the 5 diodes I received some days ago. The first one, is the one I bought from a member of this forum and it was spected at 502,9 nm and very close to the value I measured. The last one is still in the diode mount. All my measurements were done at 30 mW output power and active temperature stabilization at 20°C.




The 502,2nm and 502,0nm are great diodes to try them first in my grating feedback setup, where I aim to achieve operation at 497nm. But maybe also the higher wl diodes can also be pushed there. I will test this next week and based on this I will decide which one I will probably sell and if I will order some more to pick up the 502-502,5nm ones.

Singlemode
 

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paul1598419

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Good to know that diode I measured came out very close to what you measured. I didn't temp stabilize mine, so....

I know there are members here that will be happy to buy your cast offs as they measure well below 505nm. At least at 30 mA and temperature controlled.
 

jnrpop

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Great work on the tests SM, i dont have the slightest idea how your defraction setup can stabilise a 502nm diode down to ~497nm, looking forward to understanding that better :beer:

I believe we are both located in Germany so I'd be happy to purchase one, PM incoming
 
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Alaskan

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Single mode, thank you for supplying this information, please forgive my 532 nm diode question earlier, I didn't know I was communicating with someone skilled as well as equipped to do these kinds of tests.

Chris
 
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paul1598419

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BTW, my tests with the Odicforce boost driver is it doesn't regulate current, nor does the very cheap Chinese one. A real shame as I had high hopes for that driver. It is obviously a voltage regulator and, therefore, wouldn't keep a LD from going into thermal runaway.
 
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Hi,

is there some interest in a measurement of the beam profile ( at a screen and direct with a ccd cam ), PI curve up to 250 mA (as long there is no thermal overall) or something else?

I can calibrate my optical specrtum analyzer ( 0,1 nm resolution) to an atomic reference at 460,8nm with sub Mhz accuracy, so my wl measurements will be accurate at the 0,1 nm level.

Singlemode
 

paul1598419

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Sure, Singlkemode. I have pondered that question for some time now. Depending on power level, there are several ways to test the beam profile that I have found without the need for an analyzer. Some have used different solid objects that will give way over the surface of the beam's profile giving a fairly accurate measure. it give a three dimensional picture of it. Also there are some flat surfaces that change in darkening depending on the energy density at any place in the profile. I wish I could justify getting a beam analyzer, but it is not in the cards for me.
 
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Sure, Singlkemode. I have pondered that question for some time now. Depending on power level, there are several ways to test the beam profile that I have found without the need for an analyzer. Some have used different solid objects that will give way over the surface of the beam's profile giving a fairly accurate measure. it give a three dimensional picture of it. Also there are some flat surfaces that change in darkening depending on the energy density at any place in the profile. I wish I could justify getting a beam analyzer, but it is not in the cards for me.
Since I have to measure the beam with my ccd beam profiler anyway to know the aspect ratio, so I can use the best cylinder lenses to get a nice round beam (for optimal fibre coupling) I can post the results here.

I use a 4,5 mm focal length aspheric lens in my setup, so you have to convert your beam size according to your lens. Just for information, the beam size and the focus point change slightly with increasing current.

Singlemode
 

paul1598419

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I have a question you might know the answer to, Singlemode. We use a single element aspheric lens AR coated for 405nm to 450nm or maybe a bit higher. It has a FL of ~2.3 mm and gives a large rectangular artifact to the right of the focused dot. Even AR coated glass multi-element lenses give this same artifact. It looks like a large reflection of the emitter of the diode. I don't see it at all with a single uncoated acrylic lens, but only with that lens. Even AR coatings for that wavelength doesn't mitigate this problem.
 
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I have a question you might know the answer to, Singlemode. We use a single element aspheric lens AR coated for 405nm to 450nm or maybe a bit higher. It has a FL of ~2.3 mm and gives a large rectangular artifact to the right of the focused dot. Even AR coated glass multi-element lenses give this same artifact. It looks like a large reflection of the emitter of the diode. I don't see it at all with a single uncoated acrylic lens, but only with that lens. Even AR coatings for that wavelength doesn't mitigate this problem.

What is your clear Aperture for both lenses and tje FL of the second one?

Singlemode
 

paul1598419

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I don't have an exact number for it, but it is longer. Maybe 5 mm or there about. If I understand your other question correctly, they are ~ the same aperture.

If you are talking about the f number... both lenses have the same diameter and the FL are as described.
 
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