510nm Laser Diodes

[Prototype]

They use mirrors on wire and they're moved via electric signals. Or so I was told.

 

[pullbangdead]

Sumitomo looks experimental, and apparently can't do CW yet, but Soraa looks promising, and more power (75mW) than what Nichia rated theirs for!

Not seeing Osram (or any other greenies) in your table - an I missing something?

Would be interesting to see if they were using similar or different technologies to achieve green, pullbangdead could probably give us more insight into this.

WARNING to other readers: The following involves actual science. If you have previously had any negative reactions to science, do not read. If you experience discomfort while reading, discontinue reading and seek help at an accredited institution of higher learning. (Should be no problem for you, seoguy, but you can never be too careful these days...)


They're all nitride-based diodes. InGaN/GaN/AlGaN (even AlInGaN in the case of at least Sumitomo, they published some lasers with quaternaries), same fundamental materials as blue and violet. The devil is in the details, as they say, and there are some differences, but the basics are the same.

Nichia (and OSRAM IIRC) both base their greens on traditional c-plane GaN, which is probably part of why you only see 510 or 515 numbers from them, they haven't published higher because they may very well have not made higher. It's frankly amazing that they got c-plane to go that green as it is. Their epitaxial material quality must be amazing, their level of epitaxy control is certainly calibrated at a very high level, because you have to overcome some pretty big barriers to get c-plane GaN to do that kind of stuff.

Sumitomo and Soraa both use other planes of GaN. Sumitomo has published results on semipolar GaN, the crystal plane they've used is 20-21, and they have lasers all the lay to 530nm+. Soraa, to my knowledge, hasn't publicly revealed what crystal plane their lasers are made on, they simply state things like "non-c-plane". You can make some educated guesses though if you do a bit of research, I'll leave such guesses as an exercise to the reader.

UCSB has also published results on semipolar GaN (20-21 plane again), out to something like 513 IIRC. That is university work, of course, but such information can help you understand the paragraphs above, as work done at universities is generally published in much more detail.

If you want to know more about what any of that means, I'm still around. Occasionally.