Axial Lights

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ray_parkhurst
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Re: Axial Lights

Post by ray_parkhurst »

mjkzz wrote:
Wed Jan 19, 2022 6:40 pm

No, nothing fancy, I am not even sure what you meant by "condensing optics", and if by "homogeneous" you mean if it is evenly lit, yes, I think so. Later on I replaced the UV filter (it introduced some color cast) with a piece of "thin" glass (1.1mm thick) and it worked better. Looking back, I think it was all "beginners luck", so to speak :D
My experience is "the thinner the better" for these hybrid illumination systems. Early on I invested in a Edmunds 50/50 splitter glass, but it gave terrible results, with ghosting/CAs/Distortion. It was 3mm I believe. A while back I picked up some polished borosilicate wafers intended for passive element fabrication in semi fabs. These are 700um I believe, and seem promising for axial, but I still have not tried them. I have also picked up some large cover glasses, which I believe are 170-200um, and I have a few examples of 50/50 splitter glass on eBay which are quite thin. All in line for experiments.
Last edited by ray_parkhurst on Wed Jan 19, 2022 8:22 pm, edited 1 time in total.

mjkzz
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Re: Axial Lights

Post by mjkzz »

ray_parkhurst wrote:
Wed Jan 19, 2022 6:57 pm
mjkzz wrote:
Wed Jan 19, 2022 6:40 pm

No, nothing fancy, I am not even sure what you meant by "condensing optics", and if by "homogeneous" you mean if it is evenly lit, yes, I think so. Later on I replaced the UV filter (it introduced some color cast) with a piece of "thin" glass (1.1mm thick) and it worked better. Looking back, I think it was all "beginners luck", so to speak :D
My experience is "the thinner the better" for these hybrid illumination systems. Early on I invested in a Edmunds 50/50 splitter glass, but it gave terrible results, with ghosting/CAs/Distortion. It was 3mm I believe. A while back I picked up some polished borosilicate wafers intended for passive element fabrication in semi fabs. These are 700nm I believe, and seem promising for axial, but I still have not tried them. I have also picked up some large cover glasses, which I believe are 170-200nm, and I have a few examples of 50/50 splitter glass on eBay which are quite thin. All in line for experiments.
Not sure if thinner is better, so far I am not having any issues with 1.1mm (btw, is it 700nm or 700um, 170nm or 170um?). I think the bigger the better. Here is one failed experiment -- the glass is 55mm by 55mm, it seemingly works, but close inspection shows the bronze poles are in the image, though very subtle, they are there. This is because 1. I did not paint them black and 2. the glass is too small, so some other stuff get reflected into the image. I had 100mmx100mm in another setup and it worked well.
P1030635.jpg

Macro_Cosmos
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Re: Axial Lights

Post by Macro_Cosmos »

mjkzz wrote:
Wed Jan 19, 2022 6:36 pm
I am sure yours work, I actually looked at a solution, not sure if it is the same idea and not sure if I am using the right term (it is called light separator, literally direct translation from Chinese), it looks like a prism, but sort of separating light into two ways.
What is it called in Chinese? I might know the exact term. "分光鏡" would be a beamsplitter.
There is other terms like "half transmit half reflect (半透半反)" which would equate to 50:50 T:R beamsplitter.

For real thin beamsplitters, try "Pellicle beamsplitters", they are very thin and very fragile, never touch the membrane.

ray_parkhurst
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Re: Axial Lights

Post by ray_parkhurst »

mjkzz wrote:
Wed Jan 19, 2022 7:50 pm
Not sure if thinner is better, so far I am not having any issues with 1.1mm (btw, is it 700nm or 700um, 170nm or 170um?).
Yeah, typo. Fixed to um. I almost just wrote 0.17mm.

I have only tried pellicles once. My place is too dusty. Once they get some dust on them, you can't clean them off very easily.

mjkzz
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Re: Axial Lights

Post by mjkzz »

Macro_Cosmos wrote:
Wed Jan 19, 2022 7:58 pm
mjkzz wrote:
Wed Jan 19, 2022 6:36 pm
I am sure yours work, I actually looked at a solution, not sure if it is the same idea and not sure if I am using the right term (it is called light separator, literally direct translation from Chinese), it looks like a prism, but sort of separating light into two ways.
What is it called in Chinese? I might know the exact term. "分光鏡" would be a beamsplitter.
There is other terms like "half transmit half reflect (半透半反)" which would equate to 50:50 T:R beamsplitter.

For real thin beamsplitters, try "Pellicle beamsplitters", they are very thin and very fragile, never touch the membrane.
分光棱镜, I saw a demo in an automation trade show back in 2018 and I was intrigued, it looks like a glass cube, it was a large one, looks heavy, and looks expensive, so I always have the impression of bulkiness associated with this kind of thing :D, but I think there are smaller ones.

Thanks for Pellicle suggestion, I will keep that in mind, so far what I have works well, but you never know when to use that knowledge (of Pellicle)

mjkzz
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Re: Axial Lights

Post by mjkzz »

OK, now I know it is called beamsplitter, here is a video from Edmund Optics

Macro_Cosmos
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Re: Axial Lights

Post by Macro_Cosmos »

mjkzz wrote:
Thu Jan 20, 2022 3:43 am
Thanks for Pellicle suggestion, I will keep that in mind, so far what I have works well, but you never know when to use that knowledge (of Pellicle)
No problem! Some also abbreviate "beamsplitter" to "BS". There are many types of beamsplitters. The huge and bulky looking one you are referring to is likely a beamsplitter cube which is a true beamsplitter as the split beam will not be displaced and the optical path length is the same. Advantages come in bulk and very high costs. Beamsplitters can also be used to combine light, but "beam combiner" does not roll off the tongue as well!

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