an amusing (but useless) trick

[Things]

The hardest part with multiple wavelengths in a single package is that the focal point of each colour is slightly different. If you somehow made a single die emit 3 different colours, you still wouldn't be able to collimate them properly.

[Meatball]

That's what I've been trying to say. The index of refraction depends on the material of the lens, and the wavelength. Its only the reason why prisms create rainbows! Even if the dies were very close to one another, yes they would still be off axis from each other which means only one of them would be properly centered with the lens.

The ONLY way this would work, is if they could manufacture the cavity dimensions to compensate for the difference in initial divergence that comes off the die which also depends on wavelength. The divergence would still be elliptical though.

Would make for a neat gimmick pointer... but for projecting, I doubt it could be done in this age.

[beamann]

Interesting stuff, posting to keep track of thread

[mophead]

Interesting stuff, posting to keep track of thread

Emory,

Right above the first post in every thread is a button that says "thread Tools"

Then click to subscribe to that thread.

[pullbangdead]

lots of little beams?
do you see the beams from the different emitters?

It's already been said that this isn't what you see, but I have to interject that there aren't multiple emitters at all anyway, it's a single emitter.

An RGB diode would be impossible with one die, such a setup would consist of 3 separate dies, which would lase separately. GaN can only be push so far. Collimating such a diode would be a nightmare.

Its possible that variations in the length of the die would allow other nodes to exist simultaneous inside the medium, but they would be fighting each other for energy.

GaN (Gallium Nitride) diodes such as this have only been pushed up to ~524nm. That's the absolute longest wavelength I seen achieved as reported my the media. Some shorter wavelength greens at ~515nm have been manufactured with the capabilities of a stable 500mw. But that's still pushing the capabilities of the material. Those diodes are currently available for sample testing I believe, since they are "green enough" for some projector applications. 532nm is only a wavelength achieved through the DPSS units we see all the time.

Nitride-based diodes have been published pulsed up to 531nm, and CW up to something like 525. The 515nm diodes are important because they're on conventional c-plane GaN, which means they can be made on full-size 2-inch wafers, which means they can be be commercialized much faster. Whereas the higher wavelengths are only on semi-polar GaN so far, which means full-size substrates aren't available and the diodes are not nearly as ecomonical. YET.

I'd like to see one of those in action (and, am actually pretty curious to the wavelength of this diode's green) and I'm also getting a bit curious as to other wavelengths we could pull off with GaN. Anything in between 405 and 520nm? There are some really nice blue and cyan hues yet to be explored in there....

The III-nitride system (alloys of Ga, Al, In, and N) has been used to produce any wavelength laser between near-UV and 531nm to date. They're not far into the UV, maybe ~360nm? I don't recall the lowest number off the top of my head, but the highest is 531nm, and lasers have been/can be made at every wavelength in between. Remember LEDs can already go much farther in color-space. If some big materials issues can be solved, the wavelengths can be pushed MUCH further in both directions, GaN is some amazing stuff. GaN's bandgap emission is at ~365nm, you get higher wavelengths by adding In in place of Ga, and you get lower wavelengths by adding Al in place of Ga. The bandgap emission of pure InN (Eg = .7eV) would be about 870nm, and the bandgap emission of pure AlN (Eg = 6.2eV) would be about 195nm (give or take, I could be off by a bit on those wavelengths, that's just opff the top of my head). So in theory, light can be produced anywhere between 200 and 800nm in the III-nitride material system, but there are a LOT of problems separating theory from practice at this point. Lots of materials science that needss work.

And the color space between blue and green does have some very pretty colors. Those laser light colors are quite nice.

No. Focusing each of the different wavelengths would be impossible without separating the beams, and then recombining them. Plus, the source of the white light could not be considered as a point source anymore.

You can collimate multiple wavelengths with a single lens to the same focal point, it's called an achromatic lens. It's technically multiple elements bonded together, but it functions as one lens with the focal point being the same for multiple wavelengths. Cheapest thing out there? No. But possible none the less.

[Roy G. Biv]

515nm will even give you a greater chromatic reach than 532 would.

Yellow will be more saturated with 532 nm than with 515 nm, together with a red wavelength.

[jmgallego]

Hey, hes right!.
i just did it, and theres a violet line and a green line. but they go away above threshold.

No pictures... then, it never happened

I'll give a shot tonight.

[swamidog]

sorry... been busy. i'll try to take some shots tonight.

No pictures... then, it never happened

I'll give a shot tonight.

[Vidal Wolf]

No pictures... then, it never happened

I'll give a shot tonight.

Hey try it.
Just take your 445 &........(you DO have a 445 laser dont you? )....right, so take your 445 and power it up just so its just barely emitting light & run it thru a grating in a dark room. aim it at a white piece of paper, and you should see some other colors other than blue.

[jmgallego]

Heheheh!

Yes, I do actually several 445nm diodes ready to be mount in their hosts. But only one completed.

Agh!... the lowest possible I am able to set that one is 350mW. I need to make changes on the driver (microboost) or I'll build bench model with an LM350 and try it again this weekend.

I am interested in watching that effect and measuring power of each the three wavelengths. I have another LPM that has a low scale of 0.003mW, hopefully the emmisions are in that range.

Hey try it.
Just take your 445 &........(you DO have a 445 laser dont you? )....right, so take your 445 and power it up just so its just barely emitting light & run it thru a grating in a dark room. aim it at a white piece of paper, and you should see some other colors other than blue.