Important step toward yellow LDs ?

What do you think ?

Quantum well/barrier intermixing blue-shift of indium gallium phosphide

Nice find! I would certainly love to get my hands on a 585nm diode.

So would i, but what would be the real world application for such a diode?

We mostly get diodes because industry has a reason to produce them - for dvd or blue ray drives, for projectors and such consumer goods.

Yellow lasers could be useful in projectors if they are efficient, and only once we get to the point projectors with laser sources for blue, green AND red are standard. Yellow could be used to get better white brightness if blue remains the cheapest color to install with a decent amout of power.

Don't hold your breath on this one, i guess

Benm said:

So would i, but what would be the real world application for such a diode?

We mostly get diodes because industry has a reason to produce them - for dvd or blue ray drives, for projectors and such consumer goods.

Yellow lasers could be useful in projectors if they are efficient, and only once we get to the point projectors with laser sources for blue, green AND red are standard. Yellow could be used to get better white brightness if blue remains the cheapest color to install with a decent amout of power.

Don't hold your breath on this one, i guess

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The only use that I have seen is for lighting. I read an article where some researchers combined red, yellow, green, and blue lasers for lighting, and it was indistinguishable from LEDs. Of course, the key ingredient there is yellow. Now get cooking, scientists! :eg:

Why would you need lasers for lighting? Yellow leds have been around for ages, and recently more and more efficient models have hit the market.

There is a demand for red, green and blue lasers for projectors because they can make very saturated colors if chosen right, rending a wide gamut projection.

Yellow doesn't really do much for that, but it can be more efficient than combining red and green, similarly to having white pixels in RGB displays to bump the brightness for things that don't really need color saturation per se (like phone displays in sunny conditions).

Benm said:

So would i, but what would be the real world application for such a diode?

We mostly get diodes because industry has a reason to produce them - for dvd or blue ray drives, for projectors and such consumer goods.

Yellow lasers could be useful in projectors if they are efficient, and only once we get to the point projectors with laser sources for blue, green AND red are standard. Yellow could be used to get better white brightness if blue remains the cheapest color to install with a decent amout of power.

Don't hold your breath on this one, i guess

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In the science world, if modern adaptive telescopes get cheaper, there could be a decent demand if a high power diode with really good divergence came about. Otherwise, high end RGBY projectors are the only given.

As far as these particular ones in the article go, they're by far some of the most expensive diode types currently around to manufacture, so definitely don't hold your breath for the commercial version.

Yellow lasers can be used in projectors and TVs. It's not common but some models do use yellow light sources in addition to RGB, to improve color reproduction: https://secure.sharp.eu/cps/rde/xchg/eu/hs.xsl/-/html/quattron-rgby-technology.htm

Rivem said:

As far as these particular ones in the article go, they're by far some of the most expensive diode types currently around to manufacture, so definitely don't hold your breath for the commercial version.

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Initial cost rarely says much about the eventual cost and availability. I remember blue leds being ridicioulsy expensive and apparently hard to manufacture, but 10-15 years later they were as common as the dim red ones used to be, and about as cheap too.

Perhaps these additional colors will make in into projectors to give a wider gamut, or higher intensity for yellows overal. Since cyan lasers are becoming more available as it is, there could be solutions with 5 diodes for better color rendition. I think splitting blue into cyan and 'royal blue' would be the more impressive change, but if a pure yellow instead of blended red and green could be feasibly added, why not.

Such technology would probably be introduced first in display panels, but one the consumer expectation is there from those, they could find their way into projectors quickly, especially with th newer wide-gamut standards coming onto the market.

Benm said:

Initial cost rarely says much about the eventual cost and availability. I remember blue leds being ridicioulsy expensive and apparently hard to manufacture, but 10-15 years later they were as common as the dim red ones used to be, and about as cheap too.

Perhaps these additional colors will make in into projectors to give a wider gamut, or higher intensity for yellows overal. Since cyan lasers are becoming more available as it is, there could be solutions with 5 diodes for better color rendition. I think splitting blue into cyan and 'royal blue' would be the more impressive change, but if a pure yellow instead of blended red and green could be feasibly added, why not.

Such technology would probably be introduced first in display panels, but one the consumer expectation is there from those, they could find their way into projectors quickly, especially with th newer wide-gamut standards coming onto the market.

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I'm not talking about specific semiconductors as you imply. The paper is on a fairly complicated quantum well diode. They have much bigger manufacturing issues than the usual diodes due to the specific design. The reason they're expensive has more to do with this fact.

Usually, when we see an advancement in semiconductors on the consumer level, it's because of an advancement in materials or design using roughly the same manufacturing processes. Most semiconductors use the same sorts of processes.

Demand will usually bring the prices down after a while since the investment from manufacturers isn't continual or all that big lumped in with other products they're already producing. Really just a matter of how cheap the materials are and how many buyers they've got after a while.

This one's significantly different though, so I wouldn't expect it to be sought out as a consumer device just yet. Factories would habe to buy fairly specific equipment just to manufacture these and put a lot of effort on their part in. The quality control and reliability would also be a bit too problematic for consumer products at a reasonable price. Not very conducive to mass production.

Maybe if we make a huge improvement in die sizes and quality across the industry though.

Otherwise, I think the search for a new semiconductor that will lase yellow in a more conventional diode design shall continue and be a much more hopeful situation for us hobbyists.

If there is commercial demand there it will probably be filled, either by this technology or another.

One thing it reminds me off is vertical layering on semiconductor dies, which has been possible and expensive for ages. It has never really made it to a consumer product until recently, where flash memory is done in multiple, stacked, complete layers on a single die now.

With laser diodes there is a bit of a race towards the middle, with advances coming from red-orange going shorter wavelength as well as 405/445 blue coming down to cyan and green from the other end.

I'm not sure from which end yellow will be eventually reached for commercial application, but it seems that it eventually will be as long as there is demand.

The 445 nm development was driven by demand, and so was the further development of green direct diodes replacing the fluorescent conversion of blue or even dpss.

Though I'm late I believe there are medical uses .

indeed. market drives the technology. but if it remains only in stuff like medical, it'll be like 488 diodes or UV diodes for example and won't likely come down to hobbyist level price points. plenty of yellow and orange lasers exist, but none of them are really at hobby market price points in any kind of useful quality science-wise. Diode lasers have (generally speaking) crap beam quality with few exceptions unless they have very expensive construction behind them.

ultimatekaiser said:

indeed. market drives the technology. but if it remains only in stuff like medical, it'll be like 488 diodes or UV diodes for example and won't likely come down to hobbyist level price points. plenty of yellow and orange lasers exist, but none of them are really at hobby market price points in any kind of useful quality science-wise. Diode lasers have (generally speaking) crap beam quality with few exceptions unless they have very expensive construction behind them.

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Argee 100% Unless there is a big money need driving the development a yellow diode, like for mass produced projectors, nobody is going to fund the research. At the moment yellow can be easily created by mixing red and green---why develop a yellow diode which is by no means a simple task or a certainty.

THe article is about possible 628nm red, 602nm orange and 585nm yellow electroluminescence devices not about lasers and talks only of potential applications to market their researrch---the work is nowhere near a finished commerically viable result.

The results are interesting and very losely indicate a yellow laser diode may be possible--they say "Although the structure is designed as for a single QW (SQW) laser diode (LD), the researchers do not at this stage quote any laser characteristics. "Our results show that this new QWI method technique may pave the way for the realization of high-efficiency orange and yellow light-emitting devices based on the InGaP/InAlGaP material system" Emphasis on "may", so... all we can do is wait and see.

Yeah most blue lasers are gallium doped indium nitride, if you look at the periodic table, a phosphide moiety would have more deshielded electrons which would emit photons of lower energy, and we all know E=hv, so that would have a slightly larger wavelength than the nitride. In my theory it would work and be slightly red shifted from blue, but is the indium phosphide stable enough to retain its crystal structure over a few hundred Celsius? That is my question.