Whitelight Diode

[steve-o]

What they need to make is a whitelight multiline diode (around 1 watt or so) that can be separated into different wavelengths--488nm, 532, 635 and so on... I'm not asking too much, am i? Oh, and the price: Less than a grand .. Any takers?

[steve-o]

OK, I'll answer myself..
Gee Steve, pretty stupid idea--but intriguing, After all, they can make white leds now(which used to be thought impossible) and a mixed gas laser is able to resonate at different frequency lines, so why not a laser diode? I dont know, maybe there's not much interest in this subject or the technology is still too young. I mean, the LD itself is only what--10 years old or less?
Yeah I guess we'll have to wait a few more years for the quantum well physicists to work on this one. I guess I'll go now before everyone thinks I'm crazy for talking to myself...
bye now
back to the rubber room--
hehehehe

[allthatwhichis]

Well... most people tend to KNOW you are crazy when you not only talk to yourself, you answer yourself... Shouldn't someone keep your rubber room locked?

[jkaiser3000]

I believe the limiting factor would be the production of reasonably priced 473nm diodes, not to mention 532nm diodes (not produced yet).

Seeing that these diodes are quite small, I think you could put them close together inside the case, and collimate the beam with a simple lens. Granted, beam quality would be crappy, but it would be white light nonetheless .

[The_Doctor]

I like the implication of the question, why is there no diode laser that can make more than one wavelength at once in a single cavity? Or is there one? Gas and liquid lasers can make multiple lines, and the energy balance can be adjusted so a single cavity resonates strongly at more than one frequency. Apart from stressing a crystal lattice, I can't see what might make it universally difficult to do it. If 2nd and 3rd harmonics can be generated with a crystal, why not generate more than one harmonic directly in a solid? Given that metal can make bells, might there be a way to generate light at harmonics not in the natural harmonic series? If so, polychromatic lasers with amazing and unique colour signatures might be made, and there might be many ways to make three lines for RGB.

If such methods are found, our current best methods will look unbeleivably primitive in comparison.

One possible problem I can see is that even if it can be done, it might be very difficult to make all lines single mode, but maybe I'm missing something, after all, I think they can all be single mode in a polychrome gas laser.

[yaddatrance]

Actually I think that they *don't* make "white" LEDs... AFAIK they're blue leds which activate a white phosphor so it outputs white. The actual diode portion is blue... By the same logic, you can pump a slurry of C60 and make white...

Either way... I'd *so* buy one if they made it

[dave]

AFAIK they're blue leds which activate a white phosphor so it outputs white. The actual diode portion is blue...

Thats how i understand them to work....In fact, if you look at a white led, in its off state, i believe you can see a yellowish blob of phosphor..

[steve-o]

Yeah talking to myself and answering back. hmmm. Now about those little voices in my head--They keep saying "build another laser..build another projector" They're DRAINING MY WALLET!! Maybe the Doctor can help me..or maybe I just need to go over to the Lounge for a strong gin& tonic. Kinda early though -it's 7:30 am here..
Seriously though thanks you-all for the thoughts. I would *so* buy one too if they could design & build them.
Yadda, i tried reading up on C-60..umm.. greek to me. Are you a chemical engineer? Could you make that lase somehow?

Steve

[buffo]

The closest thing I've ever seen to a true "whitelight" diode laser is the whitelight DPSS solution from Jenoptik Unfortunately, they're crazy expensive, and they're pulsed. (But they have pretty good color mix, at 446, 532, and 628 all from a single unit. If the red was 647 it would be perfect!) Granted, the pulse rate is high enough that you can still do graphics and stuff, but because it's a pulsed laser it makes the MPE calculations harder.

Still, that's not a direct injection solution. And based on my understanding of semiconductor physics, I really don't see a multi-wavelength direct-injection diode in our future. Which leaves us with either multiple diodes and lots of optics, or the stupidly expensive DPSS solution that Jenoptik has come up with. Sigh...

Adam

[JimBo]

Where there is a problem there is also a solution.
The solution however will be found by looking at things from a different angle that seems illogical, but once found will become logical.

Jim