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Oh yeah, and because I know some of you care, (and for teh lulz).....these diodes aren't made by Nichia.

Ya. And I'm very disappointed this got no response. Nothing? A black line on a high-mag sem image of the facet of a laser diode? Aw, shucks. I think you're pretty swell too.

Looking at my own images again, there is a difference between the A and the H/M. It's not the diode itself, but the submount. The first SEM is the H/M, the second is the 9mm, and the third is the A. Of course you can see the square component, probably an ESD protection or something like that...

Honestly, I didn't even think about measuring the wires themselves. They all look the same to me, I think? You can try and compare them in the images I reckon. Also, I confirmed that the microscope calibration is currently off, it was right the first time I measured an "A" diode, so they're...

Got Dave's 3 diodes in the mail today: H, M, and A. Got images in the microscope, measured, etc. Haven't uploaded images yet, but thought I'd go ahead and post a quick update: The diode itself, in every way visible through a microscope, is identical in all 3 lasers. The dies are the same...

We'll see how the next batch of images comes out, maybe my pictures would be worth the effort. Hell, I'm curious enough about these that I might even stick them in the SEM too. The optical microscopes here will definitely show cavity length and ridge width, but there's another one or 2 things...

Anybody remember my diode microscope pics? I'd like to compare A, M, and 9mm with enough mag to measure ridge width. Any volunteers?

Don't forget to include another factor...time. How much of a difference in final operating temperature is your time worth? If I told you that you could lower your diode's operating temperature by 10C if you spend several hours doing all of this analysis, is that worth it to you? It's not to...

:: puts on materials scientist hat :: Everybody is talking WAY too generally here. In general, for a heatsink you want high thermal conductivity and high heat capacity. You want both. Like anything else in the world though, you can't have both, so you have to make an engineering decision...

This isn't always true. In my department, >90% of people enter straight into the PhD program with only a bachelor's degree, and in fact never earn a masters degree. The goal is a PhD from the beginning. The department won't fund anyone who wants only a masters, and the same is true in many...

You'll see a color due to interference. Like the rainbow of colors you see when there's a layer of oil on water, the colors are due to interference, and the color depends on the thickness of the film. There's a rainbow effect with oil-on-water because the thickness is different everywhere...

I'm pretty sure most of the commercial diodes have coated facets, it's nothing new. I've only ever looked at the 445nm diodes that closely to see it myself, so I'm not certain about any others in particular.

Some people have said the facets will degrade with exposure to air. This is true for GaN facets...but these 445nm diodes have coated facets. The facet of the semiconductor itself is literally coated with glass, the semiconductor isn't exposed. An uncoated facet will degrade, there is...

It still works, right? Use it til it dies, just like every other laser you own. There's no reason to treat it any differently, except being more careful to not get dirt in it.

It's not going to hurt anything to be exposed to air, I promise. No significant effect from the lack of a can alone. The only thing is that it's easier for a foreign object or contaminant to mess it up though.

LOL, I've seen the article before, but I still love the picture of Shuji...young, and actually in a lab. Wearing a labcoat and everything. Here he is now: The best published records are now down around something like 10^7 cm^-2, or something like that, I don't recall off the top of my...

Disagree on all counts. As do many others, since they just finished a round a fundraising with almost $100million in new investment. This bulb isn't meant to compete with incandescent, it's a drop-in halogen replacement. Not even general halogen replacement, but a very specific form-factor...

Naah, I think they'll be alright. But we'll see. Yeah, their stuff was private, but did you at least go see Shuji receive his Emmy Award?

On the subject of color difference, ie how far apart colors "look", a LOT of work has been done on that too. Here's a link to CIE work, which goes way beyond the 1931 chart, up to today's standards: Color difference - Wikipedia, the free encyclopedia For the purposes of this discussion...