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[badger1666]

Fired it up eric and smiled , 0.99 mrad whoop whoop best laserwave i have had so far
One minor problem it has an tem01 beam untill it warms up, then its all good
Cant check modulation untill i finish the build

[buffo]

Finally got a chance to play with one of my new CNI greens for a while tonight. Did some power measurements at various modulation levels, and I also did a long-throw (~90 ft) divergence check.

The short version is that it's got a 2 mm beam at the aperture, the divergence works out to around 1.4 mrad, and the power curve is very linear once you get above the lasing threshold of 1.6 volts. All in all, not bad for a laser that retails for just over $500. Runs nice and cool, and delivers around 20% more power than it's spec'd for. Perfect laser for beams or close gfx work. If you want the nitty gritty, read on...

I powered it up and set it on a large aluminum baseplate and positioned the power meter about 2 ft away. I used one of those ophir heads with a simple +/- 12V supply and a DVM to check the power, but I also double-check those numbers against my home-made "Kenom-meter" that DZ made for me several years ago. They matched up within 10%, so that made me happy.

Anyway, like I said, up until 1.6 volts, you've got nothing. Zero output. And even once you get above threshold, you really don't get much light output until you're over 2 volts on the modulation input. But once you pass that point, hang on! Power builds quick! It appears that peak power (or very close to it) is reached just past 4.5 volts. The unit was spec'd for 1 watt, and was making just north of 1.2 watts at a full 5 volts on the modulation input. But even at 4.5 volts, I already had 1.15 watts on the meter. You can see the power drift up even more slowly as you creep past 4.8 volts, but I'm not sure if that was actual modulation response or just thermal drift. We're only talking about 50 to 60 mw at the very top end of the range though.

I've attached a .pdf file that shows an X/Y plot of the power output vs the modulation voltage. The curve is surprisingly linear throughout the vast majority of the power range.

As for the beam quality, it appears to be round, gaussian, and TEM00 in the near to mid-field range. (Say, out to around 50 ft or so.) Beyond that, it is apparent that the beam is not exactly circular, but slightly oval-shaped. Still, I didn't see any other transverse modes, nor any evidence of mode-hopping. But with the higher divergence, at distances beyond 50 ft the beam is starting to get a bit too large for quality graphics.

Initial beam diameter at the aperture is 2 mm, or possibly slightly less. Difficult to get an accurate reading at full power because of all the reflected light. (Holy shit this thing is bright!) And at ~ 90 ft from the aperture, I measured a beam diameter of 40 mm. So that works out to 1.41 mrad. Not bad, but not as good as I had hoped. Still, if you pair it with a 445 blue and a fat 637 red, it will match up just fine, and for high power beam work, you won't ever notice the difference. (But I wouldn't want to use this laser to try to display intricate text or graphics at distances much over 50 ft...)

Like I said, for just over 500 bucks, it's a bargan for most uses. But if you want to run graphics shows on the face of the Hoover Dam, you're probably going to need a different laser to do it...

Adam