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Anyone here grind lenses

trussmonkey25

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Well we all know these big diodes have astigmatism. Can anyone grind a singl lens to correct for it? More cylidrical for the fast axis and less on the slow? I never seen anyone attempt this. Im sure each different diode will require a different setup for the grinder just like an optimologist would. Of course the diode and this ficticuse lens will have to be alined according to the axis. Am I crazy or could this work? The lens would be based on two centers instead of one...oval in shape.
 



Alaskan

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I'm not aware of anyone here who has, but you can find someone who does for their astronomy hobby, not as common today as in the past, but there are still some folk doing it, but much larger lenses than we use.
 

paul1598419

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Larger telescopes use mirrors. Some lenses, but the main light capture is accomplished with concave mirrored surfaces. I am unaware of a cylindrical lens for laser diodes that comes as a circular diameter for housings we use. I have seen planters use them for some of his lasers, but they are much larger than the 9mm housings we use here. His have longer FLs and he is able to adjust them by rotating them and watching a screen. The procedure he uses is simple, but I don't see it working for pointers.
 

Alaskan

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Cylinder lenses in a round shape are not very common, I've bought a few I found on ebay, but I don't know where to get them new. I'm sure you can buy them for $ bucks somewhere. There are a few folk still grinding lenses for telescopes in their hobby, but Paul is right, the majority use mirrors these days.

I would rather buy one than make it:

 
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trussmonkey25

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Nice videos, Alaskan, I just wonder if he can modify the rig shown to grind on two axis much like a carpenter cuts out an oval.this could be a game changer
 

steve001

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Cylinder lenses in a round shape are not very common, I've bought a few I found on ebay, but I don't know where to get them new. I'm sure you can buy them for $ bucks somewhere. There are a few folk still grinding lenses for telescopes in their hobby, but Paul is right, the majority use mirrors these days.

I would rather buy one than make it:

Edmund Optics carries them.
 

logsquared

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Well we all know these big diodes have astigmatism. Can anyone grind a singl lens to correct for it? More cylidrical for the fast axis and less on the slow?
Problem would be different focal lengths in each axis of the lens. So, focus could only happen for one axis at a time.

Maybe if a special lens was ground with a negative cylinder on the backside?
 

steve001

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Problem would be different focal lengths in each axis of the lens. So, focus could only happen for one axis at a time.

Maybe if a special lens was ground with a negative cylinder on the backside?
That would be called a meniscus lens.
Edmund Optics carries negative round cylindrical lenses.
 

logsquared

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That would be called a meniscus lens.
Edmund Optics carries negative round cylindrical lenses.
Im saying the lens would be spherical on the output side and have a negative cylinder on the input side. The thickness of the lens and the FL of the cylinder would change the magnification and system FL on one axis only. Thereby, one element could have different magnification for each axis. This could, in theory, provide the beam correction with a single lens element.
 
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steve001

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Im saying the lens would be spherical on the output side and have a negative cylinder on the input side. The thickness of the lens and the FL of the cylinder would change the magnification and system FL on one axis only. Thereby, one element could have different magnification for each axis. This could, in theory, provide the beam correction with a single lens element.
I have a suspicion that such a lens would not work.
There are plano-convex rod (thick) lenses; as far as I'm aware are not useful for laser beam shaping. If you have some spare change purchase a negative cylindrical and a plano-convex lens and experiment.
 

trussmonkey25

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Each laser needs its own correction much like every eye needs its own correction. Your idea will work to some degree. I might try making a crud form of this just by shaping ice just for test of concept.
 

logsquared

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A little bit different than your idea. I wonder if this lens went into production?
Not the exact same thing. I'd say its pretty good amalgamation of trussmonkey's idea of different orthogonal grinds on the front and my idea of non-spherical correction on the back.

I also wonder if they exist somewhere.
 

trussmonkey25

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Im no physicist or eletronics person, but i shape things with my hands and imagination. Now all we need is someone to build the rig as suggested above to grind at least the face of the lens for proof of concept. When the parts for my sanwu come, Ill try the crude ice lens. Perhaps Podo can find someone over in Hongkong to try? This lens will change laserpointers forever if it ever comes to be
 




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