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Anyone remember the liquid fan diffraction grating at NOVA LASERS ?

rigormortis

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Years ago i bought a green laser pointer and a liquid fan diffraction grating from NOVA LASERS, that was fitting in front of the laser like a cap. The effect was great. It was like the like the one at the link below. I can never find that diffraction grating anymore. Can you please help me about this ? I found one at DRAGON LASERS but it doesnt fit like NOVA's.

here it is ---->https://www.dragonlasers.com/Laser-Beam-Splitters.html
and the liquid fan effect ---> https://youtu.be/U7r9J2Krip8

Thanks so much..
 



BowtieGuy

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Years ago i bought a green laser pointer and a liquid fan diffraction grating from NOVA LASERS, that was fitting in front of the laser like a cap. The effect was great. It was like the like the one at the link below. I can never find that diffraction grating anymore. Can you please help me about this ? I found one at DRAGON LASERS but it doesnt fit like NOVA's.

here it is ---->https://www.dragonlasers.com/Laser-Beam-Splitters.html
and the liquid fan effect ---> https://youtu.be/U7r9J2Krip8

Thanks so much..
That youtube video is just showing a standard fan type grating similar to the Dragon Laser one.
I have those Dragon Laser models myself, and they are a pretty decent grating, IMO.

Edit: Here is a photo of one of my 488nm lasers with the Dragon Lasers fan diffraction grating.


 
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paul1598419

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You can get the same effect by using a 1000 l/mm diffraction grating and placing it in front of any laser. It would be fairly simple to put one into a cap so you can just pop it on or off. If you want the lines closer together just use a grating with fewer lines/ mm.
 
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rigormortis

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You can get the same effect by using a 1000 l/mm diffraction grating and placing it in front of any laser. It would be fairly simple to put one into a cap so you can just pop it on or off. If you want the lines closer together just use a grating with fewer lines/ mm.
Thanks so much. Where can i find it ?
 

paul1598419

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You can find them on eBay for as little as $1.00. Just look for diffraction gratings. The cheapest ones are plastic in a cardboard holder. I bought a sheet 20 cm^2 several years ago to cut pieces out of before I got my first spectrometer. They are just an amusement now.
 
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rigormortis

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You can find them on eBay for as little as $1.00. Just look for diffraction gratings. The cheapest ones are plastic in a cardboard holder. I bought a sheet 20 cm^2 several years ago to cut pieces out of before I got my first spectrometer. They are just an amusement now.
thanks so much!
 

Cyparagon

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You can get the same effect by using a 1000 l/mm diffraction grating and placing it in front of any laser.
Not quite the same effect. 1000l/mm will only give you three total beams. You'd need a much lower line count to get as many beams as the novalasers grating.
 

paul1598419

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Not quite the same effect. 1000l/mm will only give you three total beams. You'd need a much lower line count to get as many beams as the novalasers grating.
No you will get more than three beams out using 1000 l/mm. If you had quoted my entire post, you would have shown it said you will get more lines closer together using fewer l/mm.
 

paul1598419

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If you show the spots from the grating on a wall about 15 feet away you will see many more than three. Like I said, if you want your lines closer together use fewer lines/mm. I get six lines against a far wall using a 1000 l/mm grating. If you look further out you can see it is because the angles are greater between the lines when there are more lines/mm in your grating.
 

Cyparagon

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I just checked with several different colors. Violet and deep blue have a very weak second order that shows up as a soft blob rather than a dot, but green through red do not.

The point remains, 1000l/mm grating does not produce the effect of the dragon lasers fan. Or maybe all of mine are mislabeled. Do you have a photo to prove what you say?
 
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paul1598419

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The reason you only see three lines is because you didn't take the photo with the laser beams coming at you like BowtieGuy did, but took the photo at the grating going out from it. My statement in the first post is correct that you can get the same EFFECT by using a 1000 l/mm grating because you will see lines diverging from the gating coming toward you. If you want to get as many lines as possible, the angle between the lines must be more acute. This means you you will need to use a grating that has fewer l/mm than 1000. The effect will be the same, just that the angle will be more acute between the beams, so there will be more of them. My use of the 1000 l/mm was because it is far more accurate when you are trying to measure the wavelength of a laser. I think you know all this, so what is your point? That it won't look exactly like the one in post #2? If that is what you are trying to get at, then yes, like I said in my first post about this you will need fewer lines per mm.
 

icecruncher

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Dragon's gratings are soo much better than the cheap plastic ones. plus you don't have to worry about melting them with high power lasers that can be a problem with the ultra cheap ones.

I wouldn't mind getting a few more. However I remember buying a full set of 4 different ones, three were the same size but one was oddball. (don't remember what the patterns were- haven't pulled them out in a while)

Just realized the 4 kinds are posted in link - 2 styles of fan and 2 styles of grid- Dummy me :banghead:
 
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Cyparagon

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The reason you only see three lines is because you didn't take the photo with the laser beams coming at you like BowtieGuy did, but took the photo at the grating going out from it.
Excuse you, I was there when I took it. You don't get to tell me the geometry of my own photo. What's worse, is it doesn't matter any way.

But since you're so hellbent on this, so be it.







3 beams from the back, Paul.







3 beams from the front, Paul.

What else am I doing wrong, Paul? Are you running out of excuses yet, Paul? Because this is getting silly, the amount of proof you require to revert your position on something so simple.
 
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