Anisotropic illumination.

[Plasmid]

Does anyone know how to, or has tried to insert an anisotropic filter below the specimen (in this case water samples) in order to illuminate the sample from below while using a pair of linear polarizers. I noticed that bacteria appear with a lot more contrast when viewed while on the surface of a grain of sand and viewed under polarization, the same can be said for internal structures in ciliates, and so I would like to replicate the whole effect across the slide sample. I've tried placing a strip of clear tape on thr bottom of the slide but the effects were mild. Im wondering if anyone knows of any type of material that can be used to amplify this effect? I looked at anisotropic tape that is used in electronics but it doesn't appear clear enough for a sub 100w substage light source. For reference Im aiming at the quartz birefringence.

[Greg Howald]

Well... I don't know if it will help but there are a couple of things I have tried.
I made a polarizing filter for the filter holder under the condenser. I glued a toothpick on the edge of it so I could rotate the filter while it was in the filter holder.
Using my normal polarizer under the specimen and the analyzer in the head in 90 degree cross polarization, the polarizer in the filter holder could be rotated to change the degree of polarization.
The other thing I did was to place a one way mirror sheet under the specimen and play with polarization that way. Effects were very interesting.
Greg

[Plasmid]

Here's two crude videos I quickly put together to demonstrate the effects.
Blue one with packaging tape
Yellow with scotch office tape

[Plasmid]

Well... I don't know if it will help but there are a couple of things I have tried.
.
The other thing I did was to place a one way mirror sheet under the specimen and play with polarization that way. Effects were very interesting.
Greg

Hi Greg, Im interested in trying this out, but I'm not familiar with the one way mirror sheet, could you share a pic or link?
The current setup Im using has the polarizer integrated to the condenser with a turn wheel.

[Greg Howald]

It's a window covering plastic sheet that's about 17inches by 30inches. Cost all of 8 bucks. I've tried a few things with it but am really just starting to experiment.
Greg