DIC Question
Re: DIC Question
Breaking Taps had a video showing the fringing on a molded acrylic lens, which I think was actually polypropylene:
https://youtu.be/JNXgHbBIRYQ?t=1016
[I know I had added the link, but it disappeared. So added it.]
https://youtu.be/JNXgHbBIRYQ?t=1016
[I know I had added the link, but it disappeared. So added it.]
Last edited by microb on Wed Jul 21, 2021 5:53 am, edited 1 time in total.
Re: DIC Question
Got 3/32 bar from McMaster per Rathi, unsurprisingly shows similar strong inherent birefringence as the 1/16 and 1/8 I already had, didn't bother taking a photo. So why does Rathi fig. 3(b) shows so little shift of the fringe pattern? McMaster changed suppliers, or supplier changed manufacturing method? One confusing thing about fig. 3(b) is that going by the 10 mm scale bar the diameter of the circular stop is slightly more than 20 mm, but the widest bar shown in fig. 2 is 20 mm? Is your interpretation of 3(b) that it is showing close to the full width of the bar? McMaster currently does not sell bars narrower than 1" so maybe the bar in 3(b) is actually 1" and the 20 mm in 2(a) was just some preliminary sketch they didn't actually follow? (Seems like a lot of trouble for no obvious benefit to buy 1" bars and cut them down to 20 mm...)
Link is missing...
Re: DIC Question
I know I had it there, so I edited it above. What I thought was interesting is that he molded the lens and where the plastic was pushed in there was more stress. So he built into the plastic a level of stress. I wonder if that could be done but I guess the rig with the screws is adjustable and the manufacture with a mold would probably be less predictable.
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Re: DIC Question
The Rathi paper isn't great for an apparently peer-reviewed publication. It would appear she was just an undergraduate student at the time - https://you.stonybrook.edu/sonikarathi/ ... nd-grants/hans wrote: ↑Wed Jul 21, 2021 3:40 amGot 3/32 bar from McMaster per Rathi, unsurprisingly shows similar strong inherent birefringence as the 1/16 and 1/8 I already had, didn't bother taking a photo. So why does Rathi fig. 3(b) shows so little shift of the fringe pattern? McMaster changed suppliers, or supplier changed manufacturing method? One confusing thing about fig. 3(b) is that going by the 10 mm scale bar the diameter of the circular stop is slightly more than 20 mm, but the widest bar shown in fig. 2 is 20 mm? Is your interpretation of 3(b) that it is showing close to the full width of the bar? McMaster currently does not sell bars narrower than 1" so maybe the bar in 3(b) is actually 1" and the 20 mm in 2(a) was just some preliminary sketch they didn't actually follow? (Seems like a lot of trouble for no obvious benefit to buy 1" bars and cut them down to 20 mm...)
Link is missing...
I suspect things in the paper have been somewhat idealised (as students often do... ) The paper has never been cited by anyone else. I'll still have a go at getting it working next month. If I don't get anywhere by the end of August then I'll abandon it.
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
Re: DIC Question
Agreed.
However, the likely audience of her paper is hobby microscopists rather than researchers, and hobby microscopists apparently rarely publish papers... Her supervisor and/or corresponding author would know more about it.
I am still crossing fingers to see a true DIY-DIC come to life !
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Re: DIC Question
Yeah, but as you see from the above link she did it as a freshman undergraduate summer project, not even a final year honours-type project. It won't have been done especially for amateurs as the Applied Optics journal isn't easy to access. I can get to it via my Uni (I'm a registered student). Her undergrad supervisor probably didn't pay much attention to it... She's now a 'biomedical engineer' rather than any kind of microscopist.Hobbyst46 wrote: ↑Wed Jul 21, 2021 4:43 pmAgreed.
However, the likely audience of her paper is hobby microscopists rather than researchers, and hobby microscopists apparently rarely publish papers... Her supervisor and/or corresponding author would know more about it.
I am still crossing fingers to see a true DIY-DIC come to life !
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: DIC Question
Saul seems to have gotten it working, though he only posted the two pictures.
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Re: DIC Question
I guess now saul is too busy looking at everything in halo-free high contrast
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination
Re: DIC Question
Very interesting subject, will definetely give it a try. I have some experience with metalworking, although at the monent I don't have access to milling machines and lathes. Also I know some people who make scale models of buildings and they must have lots if different polycarbonate sheets. I've read the paper and one thing really bothers me - the relay lens to move back focal plane away from the objective. I think that it is better to find some objective with lower magnification with back focal plane far enough to place the prism and polish the technique with it, and then move to all those fancy lens.
I have only one question, how to find the back focal plane? I have two sets of identical Carl Zeiss Jena Planachromat objectives, RMS/160, one set is for phase contrast and one for polarisation (strain-less glass). Also I have set of infininty-corrected planachromats and one planapochromat, for use with reflected light illuminator (Auflichtkondensor). And a phase telescope (aka centering microscope), if it will help.
Does the back focal plane of infinity-corrected objective lie before or after tube lens?
I have no idea about some optics stuff, I am closer to mechanics as I've studied jewelry and machining in college.
I have only one question, how to find the back focal plane? I have two sets of identical Carl Zeiss Jena Planachromat objectives, RMS/160, one set is for phase contrast and one for polarisation (strain-less glass). Also I have set of infininty-corrected planachromats and one planapochromat, for use with reflected light illuminator (Auflichtkondensor). And a phase telescope (aka centering microscope), if it will help.
Does the back focal plane of infinity-corrected objective lie before or after tube lens?
I have no idea about some optics stuff, I am closer to mechanics as I've studied jewelry and machining in college.
Gear list:
CZJ NfPk and Polmi A w/ 45mm apo objectives, Phv, Epi Pol, trinocular
Gamma Hungary 3D-condenser
LOMO ОИ-28 Fluorescence Attachment
Set of Leitz Photar macro lens
Nikon D500 DSLR
LOMO МС-2 microtome
CZJ NfPk and Polmi A w/ 45mm apo objectives, Phv, Epi Pol, trinocular
Gamma Hungary 3D-condenser
LOMO ОИ-28 Fluorescence Attachment
Set of Leitz Photar macro lens
Nikon D500 DSLR
LOMO МС-2 microtome
Re: DIC Question
Ha ha , partially true , I made a little bit different setup, have to make normal photos of it and post it...BramHuntingNematodes wrote: ↑Wed Jul 21, 2021 6:28 pmI guess now saul is too busy looking at everything in halo-free high contrast
Re: DIC Question
I don't any reason to doubt the final results in Rathi, most likely just a change in the 3/32" material McMaster sells (as mentioned earlier the 7/32" I have appears roughly consistent with fig. 3(b)) and maybe some of the implementation details are incorrect due to hurried (summer project) paper-writing.
https://www.microbehunter.com/microscop ... =6&t=11378
https://www.photomacrography.net/forum/ ... p?p=269570
I wasn't sure if that was actually DIC. I didn't see Saul claim it was, and this post seems to indicate that the splitting plane of the upper beam is not conjugate with the objective BFP?
Are there any details other than these two threads?Scarodactyl wrote: ↑Wed Jul 21, 2021 6:22 pmSaul seems to have gotten it working, though he only posted the two pictures.
https://www.microbehunter.com/microscop ... =6&t=11378
https://www.photomacrography.net/forum/ ... p?p=269570
I wasn't sure if that was actually DIC. I didn't see Saul claim it was, and this post seems to indicate that the splitting plane of the upper beam is not conjugate with the objective BFP?
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Re: DIC Question
https://www.researchgate.net/post/Is_th ... ctive_lens
The method suggested by Paolo Pozzi works really well: shine a laser pointer through the objective and measure the size of the projected image at various distances.
Re: DIC Question
Thanks a lot, just what I needed. Time to make optical bench from Lego parts and laser pointerviktor j nilsson wrote: ↑Wed Jul 21, 2021 10:27 pmhttps://www.researchgate.net/post/Is_th ... ctive_lens
The method suggested by Paolo Pozzi works really well: shine a laser pointer through the objective and measure the size of the projected image at various distances.
By the way, how exactly the prism must be located in relation to back focal plane? The plane must "cut" it in two (for example for 6 mm thick prism the plane will be exactly 3 mm from the surface), or as long as the plane is just inside the prism everything will work?
Gear list:
CZJ NfPk and Polmi A w/ 45mm apo objectives, Phv, Epi Pol, trinocular
Gamma Hungary 3D-condenser
LOMO ОИ-28 Fluorescence Attachment
Set of Leitz Photar macro lens
Nikon D500 DSLR
LOMO МС-2 microtome
CZJ NfPk and Polmi A w/ 45mm apo objectives, Phv, Epi Pol, trinocular
Gamma Hungary 3D-condenser
LOMO ОИ-28 Fluorescence Attachment
Set of Leitz Photar macro lens
Nikon D500 DSLR
LOMO МС-2 microtome
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- Joined: Tue Jul 07, 2020 1:51 pm
- Location: Scotland
Re: DIC Question
Hi Hanshans wrote: ↑Wed Jul 21, 2021 9:14 pmI don't any reason to doubt the final results in Rathi, most likely just a change in the 3/32" material McMaster sells (as mentioned earlier the 7/32" I have appears roughly consistent with fig. 3(b)) and maybe some of the implementation details are incorrect due to hurried (summer project) paper-writing.
Are there any details other than these two threads?Scarodactyl wrote: ↑Wed Jul 21, 2021 6:22 pmSaul seems to have gotten it working, though he only posted the two pictures.
https://www.microbehunter.com/microscop ... =6&t=11378
https://www.photomacrography.net/forum/ ... p?p=269570
I wasn't sure if that was actually DIC. I didn't see Saul claim it was, and this post seems to indicate that the splitting plane of the upper beam is not conjugate with the objective BFP?
I'm keeping an open mind but still a bit sceptical now. The lack of anyone citing the paper and no supplementals is a concern. In principle it should work but I don't know that I'd trust the results from a 1st year student! I should mention that I've only recently been able to access Rathi's paper via the Applied Optics page as it wasn't accessible to me, although other papers from the same journal were. Previously I only had the copy that was posted on here. Saul's images look interesting but they are taken with a 20x objective so it's not clear exactly how he set things up - presumably in a similar manner to normal DIC? DIC is mediated by refractive index gradients and I couldn't really see/identify any of them in Saul's onion pics...
The DIC devil is in the details!
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: DIC Question
Here's the Olympus Nomarski DIC setup reference, if anyone's interested:
https://www.olympus-lifescience.com/en/ ... iguration/
Louise
https://www.olympus-lifescience.com/en/ ... iguration/
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
Re: DIC Question
I think this post is saying that the upper beam (in the slider to the left of the condenser in the first photo) goes into a slot just above the objectives where a similar 3D-printed slider containing a tube lens is shown in the first photo in this post.LouiseScot wrote: ↑Thu Jul 22, 2021 12:39 amSaul's images look interesting but they are taken with a 20x objective so it's not clear exactly how he set things up...
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Re: DIC Question
Yeah but there's no detailed info about how he set up the prisms etc. Like how he got the fringes to align etc. Maybe, unlike me, he found it easy to get the patterns to match the 20x Nomarski prism! I was hoping to get a sheet of Lexan but the seller sent me Impex brand instead It does annoy me that Ebay sellers in the UK advertise Lexan but can't supply it..hans wrote: ↑Thu Jul 22, 2021 4:16 pmI think this post is saying that the upper beam (in the slider to the left of the condenser in the first photo) goes into a slot just above the objectives where a similar 3D-printed slider containing a tube lens is shown in the first photo in this post.LouiseScot wrote: ↑Thu Jul 22, 2021 12:39 amSaul's images look interesting but they are taken with a 20x objective so it's not clear exactly how he set things up...
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
Re: DIC Question
I interpreted this as saying that the strong blue and magenta background was interference colors from the beams/polarizers, which would indicate that setup differs from normal DIC:LouiseScot wrote: ↑Thu Jul 22, 2021 4:28 pmYeah but there's no detailed info about how he set up the prisms etc. Like how he got the fringes to align etc.
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Re: DIC Question
Hopefully he'll clarify at some point!hans wrote: ↑Thu Jul 22, 2021 5:16 pmI interpreted this as saying that the strong blue and magenta background was interference colors from the beams/polarizers, which would indicate that setup differs from normal DIC:LouiseScot wrote: ↑Thu Jul 22, 2021 4:28 pmYeah but there's no detailed info about how he set up the prisms etc. Like how he got the fringes to align etc.
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
Re: DIC Question
To control the strain applied and not damage the surface, wouldn’t it be better to cut the poly sheet to have supports with more surface area that a rig can make contact with. For example, instead of press point from a rod, what about spike with these blue surfaces to interface with some metal that can be accurately pressed in, maybe even torqued?
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Re: DIC Question
I have no doubt, that the method works - as long one has the suitable stress gradient, this is just a question in aligning the suitable parts of the material with other optics components. Indirect proof is also the images of the material between the polarisers, as the created patterns are pretty much exactly the same as with Wollaston prisms.LouiseScot wrote: ↑Thu Jul 22, 2021 12:39 am
I don't any reason to doubt the final results in Rathi, most likely just a change in the 3/32" material McMaster sells (as mentioned earlier the 7/32" I have appears roughly consistent with fig. 3(b)) and maybe some of the implementation details are incorrect due to hurried (summer project) paper-writing.
I'm keeping an open mind but still a bit sceptical now. The lack of anyone citing the paper and no supplementals is a concern. In principle it should work but I don't know that I'd trust the results from a 1st year student! I should mention that I've only recently been able to access Rathi's paper via the Applied Optics page as it wasn't accessible to me, although other papers from the same journal were. Previously I only had the copy that was posted on here. Saul's images look interesting but they are taken with a 20x objective so it's not clear exactly how he set things up - presumably in a similar manner to normal DIC? DIC is mediated by refractive index gradients and I couldn't really see/identify any of them in Saul's onion pics...
The DIC devil is in the details!
Louise
What considers the polycarbonate material, it seems, that there is great variability. I have tested this far following sheet materials:
*Palsun Palram 3 mm UV
*Palsun Palram 6 mm UV
*Bayer Makrolon 6 mm UV
*Plexiglass 3 mm
*Unknown polycarbonate 3 mm
There are great variabilities in the birefringence and stress required - 6mm Palram is not creating strong gradients, requiring lot of stress, the 3mm Palram has gradient but it is shifted down like with your material is. 6 mm Makrolon seems to be the best this far. Note, that at least partially the material cut orientation seems to play significant role, see following 45/0 degree cut orientations of the 6 mm Makrolon:
https://drive.google.com/file/d/196nXwM ... sp=sharing
The dark band has shifted to one side on 0 deg cut. I have to yet test the Palsun 6 mm and 3mm in different cut orientations.
Last edited by tpruuden on Sat Jul 24, 2021 9:21 am, edited 1 time in total.
Re: DIC Question
By the way, why didn't anyone thought about simply polishing that damn UV coat away with fine cerium oxide or other polish? I've heard that photographers polish away damaged lens coating from cheap lens this way and it works well.
Gear list:
CZJ NfPk and Polmi A w/ 45mm apo objectives, Phv, Epi Pol, trinocular
Gamma Hungary 3D-condenser
LOMO ОИ-28 Fluorescence Attachment
Set of Leitz Photar macro lens
Nikon D500 DSLR
LOMO МС-2 microtome
CZJ NfPk and Polmi A w/ 45mm apo objectives, Phv, Epi Pol, trinocular
Gamma Hungary 3D-condenser
LOMO ОИ-28 Fluorescence Attachment
Set of Leitz Photar macro lens
Nikon D500 DSLR
LOMO МС-2 microtome
Re: DIC Question
There is no visible coating, it is more of co-extrusion and mixed in additives.
Re: DIC Question
Quick low quality image through eyepiece, this is with one Sanderson prism after 50x objective and thin plastic film bottom sample holder - this is now PlasDIC recreation? I was unable to get it working reasonably with lower magnifications.
https://drive.google.com/file/d/1EHKyCn ... sp=sharing
I do not have full DIC setup to compare with but it seems something similar to weak DIC 3D effect is seen with just aligning the suitable areas of the stressed polycarbonate, even if the gradients are not exactly the same. This is cheek cells with two stressed polycarbonate pieces and crossed polarisers dropped to Leica beam path:
https://drive.google.com/file/d/1qBqUfW ... sp=sharing
https://drive.google.com/file/d/1EHKyCn ... sp=sharing
I do not have full DIC setup to compare with but it seems something similar to weak DIC 3D effect is seen with just aligning the suitable areas of the stressed polycarbonate, even if the gradients are not exactly the same. This is cheek cells with two stressed polycarbonate pieces and crossed polarisers dropped to Leica beam path:
https://drive.google.com/file/d/1qBqUfW ... sp=sharing
Re: DIC Question
Well, this is interesting - all windows are from THE SAME material. Wisely I marked the cut orientations on the protection film, that was removed... The square stress gradient piece can apparently be used on "sideways" orientation also.
https://drive.google.com/file/d/19ivjLl ... sp=sharing
Just for kicks - attempt to create the gradient directly in Leica condenser turret:
https://drive.google.com/file/d/19sVOjf ... sp=sharing
https://drive.google.com/file/d/19ivjLl ... sp=sharing
Just for kicks - attempt to create the gradient directly in Leica condenser turret:
https://drive.google.com/file/d/19sVOjf ... sp=sharing
Re: DIC Question
Ah, missed what you were saying about the protective film... so they are cut at 0, 45, and 90 degrees but not sure which is which?
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Re: DIC Question
I was wondering if anyone could point me in the right direction as to where to buy a Nomarski prism set i.e. a condenser prism (are they all the same?) and, say, a 20x objective prism? Possibly new ones but depends on the price I see various prisms on Ebay UK but it's not clear (to me) what's what.
I'm otherwise still busy with other things but hope to be back on the case by the end of the month
Louise
I'm otherwise still busy with other things but hope to be back on the case by the end of the month
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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- Location: Scotland
Re: DIC Question
Thorlabs sell DIC prisms but, of course, everything from them is expensive! A Nikon N2 Condenser prism is about £908 with tax and a 20x prism slider is the same. So starter Nomarski DIC parts for £1800.... Tempting. If anyone knows of another source for less, I'd obviously be interested Maybe there's a cheap Chinese source?
Louise
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo