Mitsubishi ML520G71...Red Holy Grail or Flashlight Fail ??

[CDBEAM]

Well...interesting...and educational...to say the least !! Of course....I NEVER say the least !!
The fun of this hobby is the journey....not the arrival. At minimum...it is a new toy to tinker with...
and who knows what innovation my arise with many, many PL'ers pushing the envelope . Most of us are not traditionally trained in Optics. So What !! T.Edison said it best....invention is 99% perspiration !! THANX for all your hard work !! CDBEAM

[logsquared]

Logsquared, Would you mind seeing how badly that clips on the galvo mirrors at 20 degrees optical? Add in some distance to simulate the dichro mirrors? Laser media test pattern, please.

Steve

I don't have any free 3mm mirror scanner sets at the moment.

The thorlabs lens cost me like $80 alone. Its was the only lens I could find with high enough NA to collect all the light. To make matters worse the diode has to be centered perfectly or the spot looks like crap. Not gonna get away with a aixiz holder!

This is a really cool diode for the money IMHO. However, I believe anyone trying to put these on 3mm mirrors should really just buy the opnext diode. Press it in a mount add a cheaper lens and your done. 200mw in 2mm beam .4 mRad!

I think these mitsu diodes are best served for high power beams with big mirrors. Next I'm gonna try to get 4 on 5mm mirrors with 1.6 1.8 mRad.

[absolom7691]

Well...interesting...and educational...to say the least !! Of course....I NEVER say the least !!
The fun of this hobby is the journey....not the arrival. At minimum...it is a new toy to tinker with...
and who knows what innovation my arise with many, many PL'ers pushing the envelope . Most of us are not traditionally trained in Optics. So What !! T.Edison said it best....invention is 99% perspiration !! THANX for all your hard work !! CDBEAM

We are also using a lot of these devices in applications they were not designed for.

[CDBEAM]

Tried the Planters concept of using two (2) A-Prisms.....each at approx 48 degree....trying to " Dodge the Bullet" of incidence reflection. See Pic. Set the mA to 500 and got 371mW with collimination lens only. A dual set of prisms cut the PO down to 301mW....or 19% optical loss !!. The mRad with dual prisms was 2.3.....with no prisms...it looked like the visor opening on Gort the Robot !!!

I tried many A-Prism angle combinations....and....as expected....the less the angle=> the less the divergence=> the lower the transmission....TWO waste beams suck....yea...whata waste !! I think the prisms are a dead end ( I know...DUH !! )....Well....might have more luck with Lava's C-Lenses....Stay tuned for more fun with this..." Red Beam Wet Dream "

CDBEAM

[dnar]

Thanks for trying this Mr Beam!

There has to be a way...

[CDBEAM]

I just HAD to throw this in !!!

[absolom7691]

klaatu barada nikto!

[CDBEAM]

klaatu barada nikto!

What does that really mean ??? mmmm ??? " Keep your Cool....or Do not fry their Earthling butts to a crisp " haha

Terrawatt wants to know too !!

[dnar]

I just HAD to throw this in !!!

Have you seen the recent remake of that movie, it's not bad.

[absolom7691]

Well, the dude's name was Klaatu so... Maybe it was "Gort, Klaatu says WASSUP!"

[mixedgas]

I'd like to see Lava's correction set with the Thorlabs collimation lens.

I'm betting that is optimal, if you can accept the loss, but alignment will require mounting hardware made in a GOOD machine shop. The issue will be where to place the clipping mask.

It still will have a tough time fitting on standard scanner mirrors and the $$$ per mW is astronomical despite the lower laser cost.

One step forward, two steps, back.

Steve

[taggalucci]

...the $$$ per mW is astronomical despite the lower laser cost.

One step forward, two steps, back.

This is exactly where my thinking is at this stage, though I commend the efforts to try and get value from these feisty stripes!

[Solarfire]

I'd like to see Lava's correction set with the Thorlabs collimation lens.

I'm betting that is optimal, if you can accept the loss, but alignment will require mounting hardware made in a GOOD machine shop. The issue will be where to place the clipping mask.

It still will have a tough time fitting on standard scanner mirrors and the $$$ per mW is astronomical despite the lower laser cost.

One step forward, two steps, back.

Steve

I don’t know… but with f=3.1 mm, NA=0.68 the resulting divergence that needs to be corrected would be even bigger than the optima with f=4mm. Aside that, a coli with f=4 appears to be sufficient in capturing the entire beam and that already gives a divergence > 8mrad to deal with. I would guess that with f=3.1 that the divergence would be > 10mrad. Ouch!
I don’t think the lava lens have quite enough magnification to fully correct a > 8mrad beam not to mention > 10mrad.

[norty303]

Have you seen the recent remake of that movie, it's not bad.

Good lord, is this the Keanu version? Did we watch the same film?

Me and the missus sat through it, but both commented that we should've walked when we first talked about it halfway through.

The fun part will be, for many users, getting used to tuning their amps for bigger mirrors and smaller scan angles.
It will be interesting to see if mirror stock can be ordered in the right thickness for bigger mirrors for existing Asian galvos. :-)

DT's are available with 7mm mirrors 'off the peg' and in the Uk at least, Rob can supply larger mirrors as an 'extra'. I would suspect the same situation exists elsewhere.

[logsquared]

I don’t know… but with f=3.1 mm, NA=0.68 the resulting divergence that needs to be corrected would be even bigger than the optima with f=4mm. Aside that, a coli with f=4 appears to be sufficient in capturing the entire beam and that already gives a divergence > 8mrad to deal with. I would guess that with f=3.1 that the divergence would be > 10mrad. Ouch!
I don’t think the lava lens have quite enough magnification to fully correct a > 8mrad beam not to mention > 10mrad.

Actually the Optima and G2 lenses don't have big enough NA to capture all the beam. With my test sample I got 250mW at .5A with G2 lens and 380mW with the thorlabs lens. I think the listed 35 deg divergence is actually a little greater. At least with my diode or more likely due to running the current higher than spec. I measured ~ 4.5mm out of the thorlabs.

The math says, tan(35) X 2(FL) tan(35) X 8 = 5.6mm beam with 4mm FL and tan(35) X 6 +4.2mm beam with 3mm FL. The clear aperture on those 4mm lens is like 4mm i think. 4/5.6 X100 = 71%. Lets take these numbers and see how they match real life findings. 380mw (thorlab power) X 71% (theoretical clipping losses from 4mm lens) = 270mW That is very close to the 250mW I measured. Also clipping with the 4mm lens is evident because all the crap around the far spot.

The divergence was around 10.5 with the thorlabs lens. No big deal if you are using cylinders to correct it.

[logsquared]

More pics.

Had some time today to knock out an adjustable mount for this diode. Works really well. Was able to center the diode for the best spot.
DSC01567.JPG

Here is the uncorrected spot at 39 feet. Sorry, best i could do with my camera. That's a 6" rule on the wall! Makes a great fan with no galvos needed
DSC01566.JPG

Here it is after the telescope. Tried to get a beam shot and spot shot at the same time. The vertical line is much brighter in the picture than it actually is. The spot is about 1/2 wide by ~1/8 tall. Not so bad.
DSC01570.JPG

Wanted to add. If anyone is thinking of buying the thorlabs lens get the unmounted version and put it in an aixis or daves holder. The thorlab holder sucks! The threads suck and are way to short.

[Solarfire]

The tests with the Optima lens (see post 40) showed no significant loss which could be the result of beam clipping. With a raw input of 305mW @ 400mA I got 294mW of output that’s < 4% loss which more or less fits in with the Optima claim for >97% transmission. So I think it’s safe to say, if there is any clipping going on it’s less than 2%. Not to mention the price difference of >300%.

[badger1666]

hmm are olike already using these diodes ?? maybe
http://www.ebay.co.uk/itm/200mW-635n...item2a144317cd

[Solarfire]

Here are some more tests with the lava cylinders.
Right up front, the cylinders are not optimally adjusted (beam spot distortion) this was just to determine the resulting divergence and beam size @ the aperture with a long (8mm) and short (4mm) fl lens.
These cylinders have an ultra-low loss of 10mW (3.3%) @ 300mW of input (pre cylinders) with these diodes.
As expected, the lava cylinders in combination with the Optima lens don’t quite meet up to the task at hand. With a resulting 1.9mrad divergence after fine adjustment I don’t expect any better than 1.7mrad.
Beam @ the aperture is 4mm x 2mm, far field @ 11 m roughly 8mm x 23mm.
The long fl used was the O-Like giving 1.09mrad. Beam @ the aperture 3mm x 5mm, far field @ 11m roughly 8mm x 16mm.

[logsquared]

The tests with the Optima lens (see post 40) showed no significant loss which could be the result of beam clipping. With a raw input of 305mW @ 400mA I got 294mW of output that’s < 4% loss which more or less fits in with the Optima claim for >97% transmission. So I think it’s safe to say, if there is any clipping going on it’s less than 2%. Not to mention the price difference of >300%.

That very interesting. Hadn't noticed you measured the raw output. I can't get my meter that close with my set-up. I only have one diode to test at the moment. This tells us... either one of our measurements is wrong or, more than likely, the divergence is very different from diode to diode.

I don't have a 4mm optima to test with. I assumed the performance would be similar to the G2 lens.

[Solarfire]

That very interesting. Hadn't noticed you measured the raw output. I can't get my meter that close with my set-up. I only have one diode to test at the moment. This tells us... either one of our measurements is wrong or, more than likely, the divergence is very different from diode to diode.

I don't have a 4mm optima to test with. I assumed the performance would be similar to the G2 lens.

I use Daves mounts with the diode installed pointing out the back which makes it possible to get close enough (4-5mm) to measure the raw output, it also depends on the thermopile head used. I always want to know the raw output power of the diodes I use in order to get accurate loss information of the optical components in the beam path. I also look at the raw beam pattern to pre select diodes for a symmetrical beam profile and illumination. In some cases I even found contaminated exit windows (with the 445nm diodes) which would have been baked in if run at full power.

I'm pretty sure there may be bigger deviations to be expected what the raw divergence of the FA and SA is concerned. Like the 445nm diodes these are also Lo-Fi.

I like that adjusable diode mount you got there, that's pretty much a must with a 3.1fl lens. Where did you get that?

[logsquared]

I like that adjusable diode mount you got there, that's pretty much a must with a 3.1fl lens. Where did you get that?

Thanks. I built it this morning. Here is another pic showing the diode holder sitting on top. It works really well. The slots in the diode holder let you turn the diode in case it got pressed in out of alignment. The 4-40 set screws allow X and Y movement. I think I am going to make a small run of them. Anyone interested?

DSC01575.JPG

[Solarfire]

Thanks. I built it this morning. Here is another pic showing the diode holder sitting on top. It works really well. The slots in the diode holder let you turn the diode in case it got pressed in out of alignment. The 4-40 set screws allow X and Y movement. I think I am going to make a small run of them. Anyone interested?

DSC01575.JPG

Well you got my attention! I'm interested.

[Stoney3K]

hmm are olike already using these diodes ?? maybe
http://www.ebay.co.uk/itm/200mW-635n...item2a144317cd

Wouldn't really surprise me. They could sell these modules with a 1-on-1 straight swap from Nichia 445 diodes to these Mitsubishi diodes and get them out the door. Not even necessary to change the set current on the driver...

[CDBEAM]

Thank you Solarfire and Logsquared. I have also trialed the good Doctor Lava's C-Lenses and concluded they WORK. .82 mRad.....with about 3% optical loss....I really could not ask for more....well 3mm at aperature would be nice too...but 5mm is what ya get. So....let's say we SLIGHTLY overdrive these....mmm...maybe to 600mA....400~450mW out the business end....not bad !!!
No crazy optics.....(1) Aspherical, (1) Plano Concave and (1) Plano Convex.....There ya go...Close enough for Jazz !! Possible good enough for beam shows...especially if one uses 40K scanners with mirrors that take 5mm beams. I will post some pics when I get a cylinderical lens mount machined up.
Thanx fer watchin !!

Note: Possible a dual set-up with a waveplate + PBS ?????

CDBEAM