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Laserlands 520nm 5mW, comparison with 532nm?

ephemere

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Hello all,

I just received this laser. It's the one that takes two 16340 batteries that some members here reviewed a while back.

This is my first laser, and I was looking for something SAFE, hence attracted to the 520nm 5mW specs. No IR to worry about, and forum members who tested this laser found it to be close to spec.

But this laser looks surprisingly bright to my eyes, and the color looks more like some pictures I've seen of 532nm. Having no other laser to compare it to, I have no way of knowing.

Is there any way, without equipment, that I can tell that I got a 520nm instead of a 532nm DPSS? And that it is 5mW and not 50+ mW? I assume the answer is no, but hoping some experienced folks will have some advice for me.

Thanks!
 

Encap

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Can you post a link to the actual laser you bought or a least a photo.?
The only pens listed on the Laserland web site are a 510nm and a 532nm which take 2 X AAA. Where did you get it if not from Laserland?

To answer your question generally speaking if it takes 2 X 16340, 3.7 V batteries and runs on 7.4V it is a 520nm direct diode laser .
If it takes 1 X 16340 or 1 X 18650 it is DPSS 532nm which run on 3.7V
 
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Immo1282

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There's not a lot of colour difference between 532 and 520. You won't be able to tell by eye unless they're side by side and even then it's tricky. One other way to tell if it's a diode 520 or a 532 is to inspect the spot shape and size, as DPSS 532nm lasers tend to have better beam specs but this is still pretty meaningless without a point of comparison in front of you.

Best way to tell is to deduce it based on the build and setup of the laser as Encap said.. If it runs on 1.5V disposable cells, it's almost certainly a 532nm laser. If you link us to the one you bought and maybe take a picture of the one in front of you :)

Either way - a 5mW 532 and a 5mW 520 are going to be pretty indistinguishable and will be effectively as safe as each other.
 

smallfreak

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Is there any way, without equipment, that I can tell that I got a 520nm instead of a 532nm DPSS? And that it is 5mW and not 50+ mW?
5mW green IS pretty bright, that's why usually you don't need more of this. If you have never seen a Laser with higher power it's hard to judge. If you are not immediately "shocked by the unbelievable brightness", then it's probably not 50mW.

To determine the wavelength you could try a home made spectrograph with a spare and empty DVD-R as grating. The angle of dispersion is directly related to the wavelength. Measuring the distance between the dots and the distance between the target and the grating, you could calculate the wavelength. Even with a simple ruler or tape you should come roughly to the correct value, even if the difference between 520 and 532 might seem small.

You cannot reliably judge the color of a Laser based on a photo shown on a monitor. Both the camera and the monitor work with mixing three distinct wavelength bands to fool the eye to some color. Each processing step adds uncertainty to what color impression you might get. Keeping the entire process carefully color calibrated is a PITA even for normal pictures. Chromatically pure colors are almost impossible to show with good accuracy. No matter what you do, it always looks wrong.

To determine the technology, you could look at the beam dot in a distance. Direct diode usually shows a small square whereas DPSS shows a clean and circular dot.

Nothing of it is easy if you have no prior experience and just one sample to look at. It is quite obvous, if you have a 532 and a 520 side by side, or a 5mW and 50mW of the same color.

addition: You might cool the laser in the fridge. If it still works well when cold, it is definitely NOT a DPSS.
 

LaserRanger

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Doesn't 532nm dpss look green with yellowish glow? At least that's how it looks like to me when I compare 505, 515, 520, and 532
 

Immo1282

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Doesn't 532nm dpss look green with yellowish glow? At least that's how it looks like to me when I compare 505, 515, 520, and 532
it's marginal to me with a 520 next to a 532, but it's a bit more yellowy. Definitely too close to be able to tell without a side by side comparison of colour.
 

LaserRanger

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Yeah but once you know there's a yellowish glow you'll look for it and you can't unsee it... I see the laserglow as like thin and short strokes of green and yellow in between like the starry night sky painting
 

paul1598419

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I suppose everyone is different when it comes to what a specific wavelength looks like. I can tell the difference between a 532nm laser and a 520nm one........and they don't need to be side by side.
 

RedCowboy

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Yes I also see 532 and 520 as distinctly different, 532 has more yellow where as 520 has more blue, I find 520 more pleasing too look at as it's closer to that perfect emerald green that I love to see on matter, however 532 should be more visible per mw
 

Immo1282

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On second sight of it - I believe that my eyes were being confused by the drastic difference in intensity of my two greens - Defocused and pointed at a distant wall I can very clearly see the difference now. 520 is a much "greener" green to my eye :)
 

LaserRanger

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This is exactly what I was referring to. In 532 I see yellow glowing around the green dot on the wall and when I move it around, it seems like there's and after image of yellow. Also I can see a "grain" to the light output while the direct diodes have a smoother light output both unfocused to a 12 inch circle on the wall. I've been able to tell slight differences between my 505 to my 515 and my 520 to my 532 and I get about 8 out of 10 times correct when guessing the wavelengths. Although I do turn on one after the other and not all at the same time.. Eyes are very delicate sensors and not all eyes are able to see the exact same color, color blindness is something I do not understand because I have not been able to see a color that I am blind to 😎👍yet...
 

smallfreak

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I've been able to tell slight differences between my 505 to my 515 and my 520 to my 532 and I get about 8 out of 10 times correct
You had plenty of occasions to learn to see the difference in a couple of similar greens and yet you only get 80% right when you try.
What makes you think someone without that experience and only a single sample can tell for sure whether it is 520 or 532?
 

cistercian

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Easiest way to tell is this...diode lasers have crappy divergence in one axis. A fat, pudgy beam in one axis
indicates it is a diode. Most DPSS lasers have excellent beam quality...diode lasers are much worse in comparison.

If your laser beam looks much fatter in one dimension then it is a diode laser. If not, DPSS.
 

cistercian

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I have a 505nm laser that uses the 18350 cell that is the shortest green I own, Side by side comparisons
are obvious. The difference is easy to see. Paul sent me a diffraction grating to measure it but between
being too busy and having the flu I have not done it yet. I hope to actually measure the wavelength
and when I do I will post it. I can easily see the difference in the 2 "505nm" lasers I own.
Both are shorter than my 510 laser which was my shortest before. But until I measure them...who knows?
 




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