Re: dIY DIC
Posted: Tue Nov 08, 2022 10:30 pm
My 20x nikon planapo works fairly well with my nikon epi dic prism.
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Assuming yours are the plan fluors marked for a .17mm cover slip rather than MPlans, they're meant for transmitted use. The 10x should resolve OK, with the likelihood of some loss of contrast if you're epi illuminating through the lens. Certainly worth a try.
Thanks for the reassurance! Fingers crossed I can get the epi DIC working with the proper 5x Epi, at least. Anything else will be a bonus!Scarodactyl wrote: ↑Wed Nov 09, 2022 8:56 pmFinite vs infinity doesn't matter. You can get away with some mis.atching with epi DIC anyway.
The 20x/0.75 gives surprisingly decent views of wafers in coaxial epi illumination without a coverslip, though of course it's significantly better with one. Oblique seems to be a little less forgiving.
These look a little like my results, but without the double-image.
Yep....looking a lot like my results, too.jmp wrote: ↑Thu Nov 10, 2022 12:59 amThis is the result of translating the prism along its shorter edge (left to right across the interference pattern, see the last image in this post):
There's still an image-doubling-and-shifting artifact, more evident in the top figure that I'm sure has more to do with the narrow prism (about ~1cm wide) and the crude jig that I used for testing:
I've had decent luck with lightly bending a 1.90mm plate. There's no way a 3D printed unit would have survived the strain I put my holder. Different scopes and optics might allow different results, however.jmp wrote: ↑Thu Nov 10, 2022 12:59 amI´m testing this in an inverted LOMO microscope that brings the back focal plane of 10x and 20x objectives to locations in the tube that were designed for sliders that hold either phase rings or a Wollaston prism for DIC (which recently surfaced in another forum thread). Easy access to the back focal plane of the objective greatly simplifies the use of Sanderson prisms. Also, instead of a prism before the condenser this system was designed to use a polarizer with a slith in a slider before the condenser (so, plas-DIC really). Again, having to fiddle with just one prism greatly simplifies things.
Initially I tested a 3D printed bending jig, but the bending force needed to generate the desired fringe pattern was more than what the plastic frame would take. I came with the all-metal contraption above to be able to apply more bending force, and still be able to place the prism in the slider slot. I imagine that a machined aluminum block would work wonders for this. Anyway, the crude jig worked better than I expected, but the edge of the prism ends up close or within the light path and my guess is that this might be the cause of the artifacts I´m seeing. Here´s a view of the interference finges at the back focal plane of the 10x objective (Sanderson prism jig inserted, but with the slith slider not inserted):
I see these interference patterns with too much bending of the plate. I also see the edge of the plate, and resultant oblique lighting on the smaller of the two plates I'm testing which is a sorta convenient way to distinguish it from actual DIC.
I agree. I am, however, struck by how fiddly my system is: the condenser must be just right as must the field and condenser diaphragms. Polarizers too must also be angled just right with respect to the lower Sanderson plate and the upper Nomarsky prism. Once dialed in, the effect is pretty mesmerizing!jmp wrote: ↑Thu Nov 10, 2022 12:59 amIn all it looks feasible to use a Sanderson prism to get DIC in this platform; milage might vary for other platforms. I see two major limitations: easy access to the back focal plane of the objective, and the size of the jig needed to apply the bending force (shorter prisms appear to require more bending force than larger ones).