New 638nm Diode

Hello all,

Haven't posted here in a while, so I thought i'd start it off with a diode I just found on the semi-reliable O-like.

Mitsubishi 638nm 2.5W red laser diode/double laser beam [OL-M-2.5W] - $129.00 : Zen Cart!, The Art of E-commerce

2.5W @ 2.8A & 2.4V doesn't sound too bad to me, given that's more efficient than most IR diodes at 37%.

While this has been already investigated, I'd like to look into this as i have an idea on how to correct the double beams. Any advice for an adequate driver would be appreciated.


AAlasers

AAlasers said:

Hello all,

Haven't posted here in a while, so I thought i'd start it off with a new diode I just found on the semi-reliable O-like.

Mitsubishi 638nm 2.5W red laser diode/double laser beam [OL-M-2.5W] - $129.00 : Zen Cart!, The Art of E-commerce

2.5W @ 2.8A & 2.4V doesn't sound too bad to me, given that's more efficient than most IR diodes at 37%.

Also notable is the classification of "double laser beam". That might be bad news for beam specs, but the power sounds like it's still worth it, assuming the information provided is correct (I have no reason to believe otherwise).

Given the rated lifetime at that current is >10000 hours, I also wouldn't be too surprised if this could be pushed to 4W or higher.

Not sure if there are bulk discounts, or who else might be interested in testing this, but regardless i'd be willing to take the plunge running it at a basic 3A. Not sure what driver to use, any help in that regard would be greatly appreciated. I don't have an LPM nor any real testing equipment, I would add, but this could blow the high power red C-mounts out of the water.

AAlasers

Click to expand...

Sorry to burst the Black Balloon of hope for higher power Red....but....this has been investigated...

The diode has been " Drawn, Measured....and found wanting "

The double beams are just an optical nitemare !! They are not parallel.

To optically manipulate, combine and correct the dual beams is just not worth the trouble....if it is even possible....IMNSHO....so...the wait goes on for a good High Power Red.

The P73 and Oclarro 63193 LD's... can and have been combined and corrected... with a fair amount of success....but...as far as I know....that is still the best option out there.....Sigh !!!

I may try to combine and correct two (2) Oclarro 63193 diodes....using the Cyan Cannon ll format for a HH version....it is somewhere down on my list of Combiner projects for 2016. :eg::eg:

Well, that's a bit of a disappointment. I suppose the post still stands for the purpose of a possible driver for this diode.

Additionally, there are creative ways to mitigate non-parallel emittance, but the easiest would probably be an AR coated FAC lens.

I think people should be looking into this a bit more than they are. A two or three beam emittance isn't necessarily a bad thing. For example, with two beams, what if one were to refocus the separate beams via a concave mirror with a hole in the centre, and construct some kind of dye, gas or crystal resonator to amplify the output? Just a thought.

AAlasers

Podo made the beams parallel with a 5X expander, but it didn't work with his 10X expander, see this thread: http://laserpointerforums.com/f50/m...3w-twin-buster-updated-output-test-92332.html

There is also a diode with 3 beams and those also look far from parallel, I remember someone posting a photo of one, I think it was Rhd, but I don't remember what thread it was in.

Alan

Pi R Squared said:

Podo made the beams parallel with a 5X expander, but it didn't work with his 10X expander, see this thread: http://laserpointerforums.com/f50/m...3w-twin-buster-updated-output-test-92332.html

There is also a diode with 3 beams and those also look far from parallel, I remember someone posting a photo of one, I think it was Rhd, but I don't remember what thread it was in.

Alan

Click to expand...

AALaser....Well...I am not schooled concerning the aforementioned mitigation techniques !! Please elaborate.

PI...Concerning the 5X beam expansion experiment done by Podo....well....just a little " Beam Cartoon " ...to keep it all in prospective !!! See pic:san::san::san:

CDBEAM777 said:

Well...I am not schooled concerning the aforementioned mitigation techniques !! Please elaborate.

Concerning the 5X beam expansion experiment done by Podo....well....just a little " Beam Cartoon " ...to keep it all in prospective !!! See pic:san::san::san:

Click to expand...

Well neither am I, just a beam expander shouldn't correct the direction of the beams like that so I can't elaborate. Am just pointing out that something odd appears to have happened. It may be worth investigating further, perhaps the right combination of optics can make the beams parallel and maybe it's not so difficult, or maybe Podo and his diode and beam expander are just an anomaly.

Alan

Pi R Squared said:

Well neither am I, just a beam expander shouldn't correct the direction of the beams like that so I can't elaborate. Am just pointing out that something odd appears to have happened. It may be worth investigating further, perhaps the right combination of optics can make the beams parallel and maybe it's not so difficult, or maybe Podo and his diode and beam expander are just an anomaly.

Alan

Click to expand...

Well....what may have happened....is the beams were expanded....and overlap....so...they appear to be parallel....but are really not.

As far as being able to put these beams in a parallel relationship....yes...it could be done.....but.....I doubt in a hand held format !!! Just not enough room to manipulate the beam in the close quarters we operate in !!

Perhaps the Podo method looks good to some ???...

And....I am sure my Combiner beams ....er....ah....stray from alignment....at infinity....but again....parallax view make the combined beams look perfect.

Beauty and perfection are both....in the eye of the beholder !!!

My post was unclear....as I was asking AALaser to elabotate on the mitigation solutions !!!

HAhahaha...typically.....I am perfectly clear !!! hahahahaha ,,,,er....maybe not !!!:angel::angel::angel:

Note....cleaned up my original post !!


Note...just looked again at the 5X beam expander pic again....not sure...but again....the slow axis may have been expanded enough to produce the perception of parallel beams. But...IMNSHO....two (2) beams is just odd....and...well...not attractive....

I have one of these diodes and am just waiting for a driver. They're actually called g84's not whatever olike said...

Podo sells the tri-beam ones in a lot of different hosts (as in complete builds) all around the $300 mark.
Will throw in that O-like keeps adding a lot of new stuff so if you haven't had a chance you should take a look.

There hasn't really been much of a reason for this particular kind of divergence mitigation in a diode, but here is a theoretical method that mimics crystal-based modules:

Condensing and subsequent optical correction of beam. Say, have a lens with a focal length of 0.5mm that's the same size as the window, replace it with this lens. That would make an extremely tight output beam, much like the output from a YVO4 crystal, that would diverge quite rapidly. The actual collimation lens would maybe be a 9mm lens with a 20mm focal length, AR coated for red of course..

That would make an output that would resemble the red beams of the lower power multimode diodes, while already having been "beam expanded" by a factor of 12 or more.

I would imagine the reason the 10x beam expander didn't work compared to the 5x is because depending on the angle of the beams from the zero-point axis, a lens that is too large or too close by virtue of being too small, will make the beams converge and then diverge after crossing.



Or, the lens is simply too far away and doesn't mitigate the angle of divergence entirely.

- AAlasers