0.9W 475nm Nichia multi-mode diodes

[planters]

I have thought a lot about that and the TEC's just don't work well enough. Those 6 stage TEC's can achieve a delta of 130C, but that is without any load. I am more confident of this after now installing 6 TEC systems in my projectors. The latest is a 3 stage unit that with 130W of driving power will drop a quad red -70 from ambient @ 50% modulation. To get another 50-60 degrees would probably require between 500 and 1,000W and the base plate would undoubted warm up quite a bit. This cooling is not linear with power input. I'm not sure of the relationship, but it is pretty hyperbolic (asymptotic). And, based on my LN2 system, I would need about -100 to see a significant color shift.

The other problem with the reds is that they are still the weak color and need at least a dual to have any hope of balancing the green and blue. I suspect that you would almost always need to run them both to drag the colors away from the blue and green. I think DTR said there might be a 700mW Mitsu coming soon and this might help counter that problem at least.

[Stiffler]

Once again, just thinking out loud, what about combining CO2 + TEC? Rather than using dry ice, you could use liquid CO2 and spray it onto the hot side of a TEC....If you have the right size nozzle & perhaps a small solenoid valve, this method would allow you to use a small CO2 cylinder (large paintball tank perhaps), stored remotely, and you wouldn't have to worry about storing dry ice. My current computer has some heat management issues, so anytime I'm taxing the processor or graphics card, I use CO2 to keep it cool (it is super jury rigged).

[planters]

Actually, I think dry ice alone, if a convenient, non-condensing cold finger could be designed to be filled from the top of the projector then most of my arguments would disappear. My complex base plate cooling schemes could be eliminated. You should see my latest projector. It uses Corsair water cooling modules. Anyway, if the cold red would by default operate as a standard RT module and when desired or available then adding dry ice would open an additional color channel. You could operate the base red warm, say 40C and its color would be in the low 640's and the dry ice module would run in the low 620's. That is a pretty good gap. If the CO2 bottle could spray onto the cold finger, slowly but continuously or intermittently then this might get even more practical. I would stay away from the TEC's because even a 20 degree differential from that -78C might increase the heat load to the CO2 by 10 fold.

[Stiffler]

Fair enough. I have some small CO2 nozzles laying around, I'll grab a bottle and see what I can come up with.

[mixedgas]

PLers have done group buys on soecialized dichros in the past. A US made, highly specialized, combiner for 650/633 set us back 150$ a piece and we had to buy 20 of them. The problem is such optics are VERY sensitve to angle, you might need to be at 37' +/- 0.1 degree for best power transfer, rarely do they hit exactly 45'.


Steve

[steve-o]

Interesting Steve. Thanks for the info. Do you remember the vendor/ manufacturer?

[LaNeK779]

wasn't it the precious semrock dichro?

[danielbriggs]

wasn't it the precious semrock dichro?

Sure was...
See item #8 for a quick-look-see transmission curve.
http://www.photonlexicon.com/forums/...ots)-of-lasers!


Dan

[planters]

I don't see the need for a special dichro. If you want to add this additional color then use a PBS for two single diodes and if you want multi diode modules then use k.edging. You will have to k. edge anyway if you will be using multiple diodes.

[norty303]

Absolutely, you just need to make sure you use the waveplate on the 445 side, until we get a suitable waveplate for the higher wavelengths.

I'm really keen to see how the 2 might combine, particularly where prism pairs are used for correction. Do you think the refractive indiex will mis-align the 2 beams, or will it go out one way in the first prism, and back in again through the second?