Sounds good.
And if anyone has a broken one that they can't measure, standing offer here to measure the dimensions on SEM/high quality microscope/whatever it takes.
Sounds good.
And if anyone has a broken one that they can't measure, standing offer here to measure the dimensions on SEM/high quality microscope/whatever it takes.
Actually I found the article from which you took the picture, it is called "Supermodes in Broad Ridge (Al,In)GaN Laser Diodes". I can't post it due to copyright. But I think it more or less answers the questions, thanks for the hint! The described behavior fits exactly the observations.
Here an excerpt from the abstract:
"Broad area (Al,In)GaN laser diodes (LDs) are suitable for high optical output power in the near UV to blue spectral range. But for ridge widths larger than a few micrometers, the occurrence of filamentation is well known. We present experimental evidence that the single filaments tend to be phase-locked with defined phase offset and build up a so called supermode. Depending on driving current a coherent or incoherent superposition of different super- modes can be observed...."
The filaments they talk about are the intensity fluctuations shown in the figure you attached. They indeed don't reflect multiple emitters but mode patterns. As observed, they differ from diode to diode, and people in need of a clean pattern, such as us holographers, may need to select the "better" diodes.
Yep, Osram has put out several good papers the last couple of years.
Nice job finding it so fast, that was quick.
The multimode beam is caused by different sets of quantum wells lighting up at different tiimes and current. Near threshold these diodes are essentially single-mode to about 60mw, with one mode lighting up,at full power they are very very much multimode like an 808nm pump diode.
Krazer did longdurance test he reached 1.75 from a single diode:
http://www.krazerlasers.com/lasers/
NOTE-
Yes the laser produced 1.76W when run at 2A, however this current is NOT safe to run the diode at, it causes a steady, permanent degradation of the diode. On the bright side all of those tests were done with a stock lens, and with a with a high(er) quality lens one should expect a slight improvement.
Well I finally found some time to build a 445nm Laser that I got
from EF... I installed it into an Aixiz Module using a 405 G-1 lens.
It is mounted in a Z-Bolt clam shell heat sink..
I did a bit of testing and here are my results...
I tested in 100mW increments and stopped at 1300mW..
I used an Opto Power Corporation OPC-PS4005 Laser
Diode Driver.
007mW ---- 220mA @ 3.95V Threshold
050mW ---- 260mA
100mW ---- 310mA @ 4.09V
200mW ---- 380mA
300mW ---- 460mA
400mW ---- 540mA
500mW ---- 620mA @ 4.46V
600mW ---- 710mA
700mW ---- 800mA
800mW ---- 890mA
900mW ---- 980mA
1000mW -- 1090mA @ 4.79V
1100mW -- 1210mA
1200mW -- 1340mA
1300mW -- 1530mA @ 4.99V
For those of you that are trying to measure raw output
on a thermal sensor without a lens... your readings will
be skewed to a greater value...
The reason for this is because the 445nm LD's case gets
really hot and when you are very close to the sensor... the
head reads the LD's heat radiation on top of the Laser's
beam.. once you are a few inches away.. that effect is
negligible...
BTW... I found a 3/8" inside diameter rubber grommet that
serves as a lens ring adjustment method to not burn my
fingers.. It fits right over the knurled lens cap..
It's cheap and it works...
[EDIT]
This was a test of the A130 LD
Jerry
Last edited by lasersbee; 06-29-2010 at 06:53.
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Nice Jerry! Glad to see you got 'er up and running.. those are some sweet numbers.