Making the Right Investment: Polarized Light Microscope Buying Guide

A polarized light microscope is suitable for observing and photographing samples and specimens that are not visible due to their optical anisotropic qualities. Simply put, certain samples cannot be clearly seen from all sides and viewpoints, but a polarized light microscope, with proper sample positioning, can successfully capture images of the sample. This buying guide provides you tips on how to purchase the best polarized microscope for you.

How a Polarized Light Microscope Works
A polarized light microscope has two key components distinct from other microscopes: polarizer and analyzer (the microscope’s second polarizer). Samples must have birefringent characteristics or able to produce two separate light waves. Polarized light techniques can make this type of specimen more clearly seen than what other light techniques such as phase contrast, dark field illumination, and fluorescent illumination, are capable of.

What to Look for in a Polarized Light Microscope

Stage – Nowadays, new polarized light microscope models often come with rotating stages. The rotating function of a microscope stage improves efficiency in teaching new users how to study specimens using this type of illumination technique. A circular stage is also ideal, and preferably with a goniometer. If possible, look for a goniometer with 1-degree divisions to further improve accuracy of sample positioning.

If the stage also comes with or two verniers, so much the better! Verniers provide even smaller measurement divisions to increase rate of accuracy. If the microscope model you are considering buying does come with a vernier, make sure it is using precision ball bearing mechanism to operate.

Check the stage clamps to see if they are working perfectly.

Condenser – Look for the Abbe type of condenser rather than other versions because this provides users with greater flexibility or control. Secondly, the condenser must be both centerable and strain-free to improve image clarity.

Polarizer – It must be pre-attached. If not, then you would have the added problem of attaching the polarizer in the exact position needed. Erroneous positioning, even to the slightest degree, can greatly affect the image produced by your microscope.

Objectives – A polarized light microscope only utilizes specially designed objectives. They may be plan fluorite or achromatic. They may also simply be achromatic as well. Never use apochromatic lenses with your polarized light microscope because mounting and other lens aspects can make it difficult to remove strain and stress from their surface.

Look for infinity corrected strain free objective lenses if you wish to invest in a new set other than the ones provided with the polarized light microscope. And as objective lenses for polarized light microscopy are normally ten to twenty-five percent higher than those used by other microscopes, make sure then that the set you’re buying are of higher grade and suitable for polarized light illumination.

Check the label regarding testing procedures. Objective lenses used for polarized light microscopes generally have to undergo rigorous testing procedures before they are released to the market.

Objective lenses for polarized light microscopes have magnification levels ranging from 2x to 100x. The free set of objective lenses a newly purchased microscope may come with four lenses – 40, 20, 10, and 4x.

Conoscopic and Orthoscopic Attachments – Orthoscopy is the study of the eye in a microscopic level. Conoscopy refers to the study of interference figures in the focal plane of a microscope’s objectives and produced by a sample with anisotropic characteristics. Polarized light microscopes are commonly used for both fields and that’s why it’s better if your newly purchased model automatically with the necessary attachments for them.

Analyzer – It is better if the analyzer of your polarized light microscope is rotating up to 360 degrees. Its rotating feature makes sure that the positioning of the analyzer is prevented from obstructing the light path. Bertrand Lens – Also known as Amici-Bertrand lens, the inclusion of this feature gives the user the ability to study conoscopic polarized light images, aperture size of the condenser, and illumination alignment. These factors are all the more necessary when one wishes to use Köhler illumination.

Compensators and Style Plates – These are inserted in a slot in the microscope’s body tube, on top of the objective nosepiece and in between the microscope’s two polarizers. Retardation and accessory plates are used to provide the necessary change of vibration direction.

At the very least, your polarized light microscope should come with the following types of compensators: Berek and Bräce-Köhler compensators, quartz wedge and wave, full wave, and de Sénarmont.

Besides these, consider looking for inclusions of a gout inspection kit, observation tubes, and objective centering adapters. Take this polarized light microscope buying guide with you so as not to forget anything listed here.