Awesome news!
A few questions -
The Sumitomo press release claims that they can somehow "tune" the LD to different wavelengths, but that it is not subject to shifts due to temp changes?
How the heck do they do that? Can they actually electrically "vary" the color of the laser light? :wtf:
Or is this just marketing hype, and they are just talking about manufacturing changes to the active layer size or Indium %???
Naah, they're just talking about while making it, they're just referring to changing indium amount (among other things) to "tune" the wavelength to different colors while making the diode. Once the diode is made, there's not a lot you can do. There re things you can do with laser diode with things like external cavities and things like that to "tune" wavelength, but those are no more or less accessible with this diode or any other diode. They're just talking to people who would say "well they have 531nm, can I get 525nm?", and telling them "yes, we can tune it to any specific wavelength in a range while manufacturing it".
Second, has their paper been published or otherwise available to those of us NOT lucky enough to be hanging-out with the likes of Dr. Nakamura and a fancy tech library like you probably have at UCSB?
It is published, the forum doesn't allow pdf attachments that I can tell. If you have a subscription to Applied Physics Express, the reference is: Applied Physics Express 2 (2009) 082101. Or, if a couple people want it, I don't reckon I would mind e-mailing out a copy or 2
Next, is the full paper that YOUR group recently published likewise available at a link someplace that us mere mortals can read it?
Ummm, come to think of it, I'm not sure I even have a copy of that paper, but I can probably find a pdf of it some time today. I think this is the reference for the paper we put out last week, but it's in the article I previously linked either way: Applied Physics Express, vol.2, p.082102, 2009. I'll see if I can rustle up a pdf somewhere around here of that one.
Finally, I noticed in the story you linked to about your group, that your new "off-kilter" m-plane design had a significantly lower threshold current (153ma). Is this advantage maintained at longer wavelengths, and do you feel that this could give your approach an edge at better efficiencies than the Sumitomo design in the green part of the spectrum?
That's one that I'm not sure I'm at liberty to discuss, as it involves future plans based on possibly proprietary information. Anything in a paper is fair game, but I don't recall off-hand what details are in the published papers and what isn't.
One thing I will say is Sumitomo's device was on a semi-polar plane [2 0 -2 1], whereas or recent paper was talking about miscuts on the non-polar m-plane [1 0 -1 0]. Most any discussion like that hinges on what plane you're using, and since the papers were talking about 2 different planes for the devices, then at least some of that discussion doesn't carry over, at least not in any straight-forward fashion. ie, a miscut on m-place won't behave the same was as a miscut on [2 0 -2 1]. There's a lot of discussion going on now about the general semi-polar vs. non-polar for green, and for blue also, as to which one will be better for which colors, and nobody really knows yet. But of course, everybody has their own ideas. Miscuts of non-polar, like we discussed, certainly have some advantages, but really every approach seems to have its own advantages right now.
Thanks!
), then build a resonant cavity for it, that be changed in lenght (and consequently, in wavelenght resonance), with a piezo positioner.
