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why only 200mW these days?

JohnD

JohnD

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Why are reds seemingly limited to "only" 200mW these days? Not much selection either. Are people just not interested in higher power reds? Of all the colors you'd want a higher power, to see the beam more clearly... Short of building one (something I have yet to attempt), are there any options?
 





The reds we use are 5.6mm diodes coming out of DVD burners. They don't need to be as powerful as Blu-ray burner diodes - so we can't drive them as hard (plus, 8x and 12x diodes seem to have proven themselves quite hardy).

High power reds (>200mW) usually have bad beam specs because they have multiple emitters. That and they usually come in 9mm or cmount packages, which are harder to integrate into a handheld. Meredith modules can hold a 9mm package, but the beam specs are still a pretty big deterrent.

-Trevor
 
I have a 500mw-1w red diode. It's supposed to be 635nm(no way to test). Hovever...

It is in a TO3 can. It's multimode. And a lot harder to get a beam then the 445 diodes. But it has a built in TEC and temp sensor.
The TEC has to be ran, or it will act as an insulator and burn up.

I suppose someone could make one more like the 445, but there has to be a reason for it to exist. I hope they do!
 
LOC and LCC reds can be stronger than 200mW. I have a LOC red at 463mA outputting 250mW. With a 650-G-1 lens it would output around 300mW.
 
Good question. There seems to be something intrinsic to the construction of these diodes that limits single mode CW operation to generally less than 1/4 watt.

Most of the red diodes out there are using AlGaInP 'recipes'. Recently GaN diode recipes have been developed - these are used to create blue (405 & 440 nm) diodes, and recently green diodes. For whatever reason the GaN chemistry and construction methods seem to be able to offer higher CW powers.

Beyond theory there's a lot of practical and 'proprietary' (secret) information that manufacturers will not divulge about these diodes. Meaning I don't know what the limiting factor is in creating a high power red, and I doubt many other people do either :) At this point if you want more than 250mW of red you're looking at DPSS or multimode diodes (bad beam specs).

I'm hoping the nascent laser projector market will create demand for high(er) power single mode red diodes. Time will tell.
 
Well, that's an improvement. However I think 1/2 to 1 watt of red is what the projector people are craving at this point.

What's the cost on that Mitsubishi diode?
 
Only ¥30,000 per, before taxes ($324.57usd)
Click to expand...

While 500-1000mW of 650nm would be good, remember that 635nm is a brighter per mW than 650nm, so not as much would be needed to compensate. And if these are destined for pico projectors, which I believe they are, they're not going to need that much power to compensate for the 515nm diodes from Nichia.,
 
I've got an old Phasor diode from a group buy. But that is from 2 years ago. I don't know what they came from, but its probably my favorite. Mostly because it was my first build and it's high power. Without the lens it was well over 300mw.

I haven't seen those since, but I really liked the power I got out of that. It's still working.

heuroscienes had some high power diodes in the red spectrum also. 500mw and up, 9mm, but probably not TEM 00

Any of those would require a build though. YOU MIGHT AS WELL START SOMETIME!
 
flogged said:
Good question. There seems to be something intrinsic to the construction of these diodes that limits single mode CW operation to generally less than 1/4 watt.

Most of the red diodes out there are using AlGaInP 'recipes'. Recently GaN diode recipes have been developed - these are used to create blue (405 & 440 nm) diodes, and recently green diodes. For whatever reason the GaN chemistry and construction methods seem to be able to offer higher CW powers.

Beyond theory there's a lot of practical and 'proprietary' (secret) information that manufacturers will not divulge about these diodes. Meaning I don't know what the limiting factor is in creating a high power red, and I doubt many other people do either :) At this point if you want more than 250mW of red you're looking at DPSS or multimode diodes (bad beam specs).

I'm hoping the nascent laser projector market will create demand for high(er) power single mode red diodes. Time will tell.
Click to expand...

GaN is magic, that's all there is to it. :na:

But seriously, it's in the materials. There's a long list of reasons, but suffice to say GaN is an amazing material, to extents which are not yet fully understood
 
I think the red it an amazing color and by far my favorite. I would love to have a 600mw-1W hand-held(very visible red beam would be sweet). I would want to build it myself.
 
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