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

[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.


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


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.


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.