DTR's Laser Shop: Diodes-Drivers-Lenses-LEDs & More

[-bart-]

Well, tapered would not be the exact description, if you have an optical ribbon that's 1µx100µ, you could roll it up to a 13µ rod, with the walls of the ribbon staying parallel at all times.

[planters]

Dnar,
Yes that is true. With the added property that those spatially coherent beams have the longest path length to preferentially extract the bulk of the energy from the medium.
bart,
There you go. Optically, you now have a 13um non-coherent "point" source. This might be easier to collimnate.

[absolom7691]

No. Without significant loss the fiber does not improve the beam. It can't alter the mode of a beam already generated. Even though what happens in a fiber is too small to see there is no magic occurring within the fiber. To help visualize this draw this out at a highly enlarged scale and trace a few rays from a diverging diode through a positive lens and into a fiber. The zig-zag rays will reflect due to total internal reflection as they pass through the fiber and as they exit a second collimnating lens will return the beam back to it's original diverging profile. The small entrance aperture of a fiber is used to act as a spatial filter to remove splash and non-uniformity.
The most direct and proven methods for improving divergence will increase the near field beam size and because this is almost always a lot smaller than the far field, more effort should be spent on enlarging the effective aperture of the scanning system while maintaining it's performance ie bigger and better amps,motors and mirrors. Go B. Benner

Thank you. This was the answer I was after (although I wish it were a different answer ). Thanks for the reply!

[planters]

DTR,
OK you get the bumps, but my question still stands re. the Phat red module you are selling. What is a reasonable maximum sustained current these will handle while still on the supplied TEC/heat sink/fan? Do you just run all the blue wires to the same positive; if so where do you ground this diode? What is the approximate beam spread with the included condenser, as in at ten feet "x" feet wide?
Thanks

[DTR]

Only time will tell what currents are sustainable. That the moment I would probably recommend around 600mA-700mA for continuous use with TEC/heatsink/fan. With an O-Like lens maybe give you about 450mW or say somewhere in the neighborhood of 650mW with a G-1/G-2. There is a little divergence and prism info in this thread. http://laserpointerforums.com/f42/co...tml#post971788

[Fenechlaser]

At logsuared,

Check out thorlabs. I've questioned this idea before, and after seeing solarfire's setup, I started checking out for lenses. I think that a 4mm and a 20mm FL cylindrical lenses should do the trick, although as solarfire mentioned in the post http://www.photonlexicon.com/forums/...-Collamination , each diode is different and therefore the end result will not be round but elliptical for some and perfect for others. I would like to test the idea but I do not have the $$ or € and time, Although I do have a milling machine at hand.

[Stoney3K]

I'm pretty surprised about the wavelength shift. On LPF there were some detailed measurements, but no indication of temperature.

The diode would shift to about 642nm at 1 Amp of current with about 0,5W of output power, which sounds like it could be a useful combo for beam shows. But the shift is probably caused by temperature, so bolting it to a TEC could yield some interesting results.

It does look like it could be a very useful diode for less demanding RGB builders on a shoestring along with the 445 Nichia and low power DPSS units.

[steve-o]

Yes, but how long before the diode fails overdriving it this much (as Steve mentioned) . MTTF (MTBF) life-tests need to be run. Having the diode(s) failing after 50 hours especially during a show would be not-too-good.

[Stoney3K]

Yes, but how long before the diode fails overdriving it this much (as Steve mentioned) . MTTF (MTBF) life-tests need to be run. Having the diode(s) failing after 50 hours especially during a show would be not-too-good.

True. DTR already did a torture test of one of these at 1,5A for over 7 minutes (outputting about 1W @ 645nm) and it didn't seem to suffer any considerable damage, nor did it heat up the heatsink it was attached to.

1,5A @ 3V means there's only 3,5W of power to dump into a heat sink, and an efficiency from wire-to-beam of over 20% (including optics losses). Which, in laser terms, is insanely efficient, even outperforming the Nichia 445 (having a lower current but higher forward voltage).

Also on LPF they found out that 1A would be the sweet spot of this diode, giving a good power, wavelength and little heat output.

BTW, did you notice the diode was wired DIRECTLY to a lab power supply on current limit? Who cares about static electricity?

[flecom]

if someone wants to donate a diode I'll gladly hook it up to a DAC and leave it running shows on a loop to see how long it lasts