Hi there,

Sure!

you can add two polarizers into your microscope system and heading for a polarizer microscope as well. many of the plastic polarizer's sheet would be used - but, have low quality. So, better quality will give you better contrast!

Before going for polarizers, you should take care of two issues:

1- a transmittance based microscope is needed, and you have to put one of the polarizers before the sample.

2- analyzer (polarizer after sample) must be after the sample. Indeed, sample must be sandwich between two polarizers.

Furthermore, you should be able to rotate one of the polarizers.

Good Luck

Thank you Ebrahim,

Why do I have to be able to rotate the analyzer? I saw some really colorful images of DNA liquid crystal, are they obtained by rotating the analyzer? Sorry I am really not familiar with this field.

Thanks

Look! for non-birefringent material the polarization of light will not change - so, if you keep polarizer and analyzer orthogonal to each other, no light will be observe at all. Therefore, you have to be able to rotate one of the polarizers (usually the first one). While for birefringent material the situation will be different, and polarization of the light after passing through the sample will change locally and point by point you will see different polarization state (polarization most likely will be elliptical). After the crossed analyzer, there will light. BUT, you might be interested to see a specific region which does not have good contrast, those that are low birefringent. In this case, in order to study these regions, you should rotate one of the polarizers and optimize the observed light by polarizer.

I have no idea about DNA, but for the case of liquid crystal - surely these will give you fantastic lovely colorful images.

Good Luck

Ebrahim, your answer helps a lot. But I am still not sure why it is colored, this is what always confuses me. Can you please give me some hint on this?

Thank you a lot!

The light source of microscope is not monochromatic, usually is a tungsten lamp, so, you have many colors as can be seen by passing it through a prism. However, refractive indices (ordinary and extraordinary) of liquid crystal (almost whole media) are wavelength dependent n:=n(lambda). Therefore, the optical path, phase, as well as change of polarization (or rotation) will be wavelength dependent. Thus, for some region Blue light will be have orthogonal polarization, while Red totally passes and between will see an intermediate case.

Does it clear now?

A complementary information regarding Ebrahin explanation.

1- Using the conventional light microsocope, set the first polarizing filter below condenser lens (easier to set over the field condenser at the microscope base) and the second filter over the objective lens (remove the head were are inserted the eyepieces lenses and set the filter on the hole of light bean pathway). Be sure they are crossed perpendicularly (90o) and results in dark field. It is important you know the polarization direction of filters and set one of these filters parallel to the microscope axis.

2- The resulting colorful images in the polarizing microscope is due to the birefringency property of anisotropic polymers or crystals. There are some biological anisotropic polymers like DNA/chromatin, collagen fibers, striated muscle cell myofibrils, cellulose of plant cells, silk fibers, etc. When the polarized light (from source) interact with samples containing biopolymers there are two optical consequences in the transmitted light. One is the “rotation” of light pathway (you will see only those rotated in parallel to analyzer filter) and the second, is the interference color generated by combinations of optical path “retardation” of quarter of wavelength (1/4) that cross the analyzer filter. The resulting colorful images are interpreted as birefringence order and can be measured in a polarizing microscope with full set of accessories. Finally, it is important to rotate your sample and set your biopolymers at +/- 45o of polarized light for correct interpretation. You will see that in one of this position will be bright and in the other will be completely dark.

Hope this additional information will help you.

Good lucky in your study.

Thank you all for these useful information, now I am confident to go ahead try it.

your microscope supplier can supply a polariser to be added at/ over the light source as a filter or as an additrional piece of equipment. It does not cost a fortune. But please do not polarise twice one polariser will neutralise the other unless is a manufactured double polariser.

Hi,

I have done this conversion many times, also for resale, working in a microscopy company.

In general, as long as you need polarisation analysis, indeed all you need is two plastic Polaroid sheets, which you can get with decent quality c/o Edmund or similar.

If your microscope does not have a filter slot above the objectives, you will need to fit the analyser under the head. This may mean that you will not be able to insert and extract the analyser quickly, which is somewhat a nuisance, as the filter darkens the light parth and as it introduces a minor degradation of image quality at high magnification. If you have a filter drawer above the objectives, you can easily place the analyser there, so that you can slide it in and out.

The polariser can be placed over the Kohler illuminator field lens. This will allow you to rotate the polariser and to remove it easily.

You should then fit on the table some way of rotating the slide. A circular centrable table is ideal, so that you can center the axis of rotation of the table on the axis of the objective.

What you cannot do easily is fitting a conoscopic lens. However, for basic observation, this is not necessary.

Finally, be aware that there are kits containing polariser, analyser and centrable table, for retrofitting onto educational microscopes. You can get them from most microscope manufacturers or resellers, and they can be less expensive that doing the job yourself, costing not more than few tens of dollars. Most of these can be retrofitted to any microscope with minor modifications only.

I hope this helps.

Hello,

You can find, at your microscope supplier, a polariser to be added at the light source as a filter. Also a piece should be pladec bettween the oculars and lents.

It is avery easy soliution. In our lab we used routinaly polarization to amiloid stain.

I hpo this can helps..

Hi

In addition to what was already suggested, you may also check this web site: http://www.microscopyu.com/

There are a lot of useful materials and tutorials there.

Including polarizing microscopy as well: http://www.microscopyu.com/articles/polarized/index.html

Hi, overlap on the condenser lens of the microscope base, two lenses polarizing filter camera. To acquire a polarized light simply rotate them over one another to obtain a single beam of light.

Mario is right. The poor man option is sometimes the best one. I used an Edmund plastic filter sheet, a good pair of scissors, and pre-school habilities. It works.

One polarizer on each side of the sample lined up for cross polarization so you cut out the excitation source, but then see birefringent light from the sample.

Behind the objective, between the objective and the eyepiece head, works. All the better if you use a dedicated polariser objective, as it has lower birefringence, giving you an overall better image.

Sorry to be way too late... I'm sure the young man learned a lot and had fun making his workaround; but if he was just working with thin slides, maybe he could have gone to the geology department at Texas Tech, which appears at a glance to have a strong program, and asked to use one of the petrographic microscopes, which are polarized, in their student optical mineralogy lab.