Introduction to the use of polarizing microscope
Polarizing microscopy is a type of microscope used to study so-called transparent and opaque anisotropic materials. All substances with birefringence can be clearly distinguished under a polarizing microscope. Of course, these substances can also be observed by staining, but some of them are impossible, and a polarizing microscope must be used.
(1) Characteristics of Polarizing Microscope
A method of changing ordinary light into polarized light for microscope inspection to identify whether a substance is single refraction (isotropic) or birefringence (anisotropy). Birefringence is a fundamental property of crystals. Therefore, polarizing microscopes are widely used in mineralogy, chemistry and other fields, as well as in biology and botany.
(2) The basic principle of polarizing microscope
The principle of polarizing microscope is relatively complicated, so I won’t introduce too much here. Polarizing microscope must have the following accessories: polarizer, analyzer, compensator or phase plate, special stress-free objective lens, and rotating stage.
(3) The method of polarizing microscopy
a. Orthscope: Also known as distortion-free microscopy, it is characterized by the use of low-magnification objective lenses without Bertrand Lens (BertrandLens), and the research object can be directly studied with polarized light. At the same time, in order to make the illumination aperture smaller, push away the upper lens of the condenser. Normal phase microscopy is used to check the birefringence of an object.
b. Conoscope: Also known as interference microscopy, it studies the interference pattern generated when polarized light interferes. This method is used to observe the uniaxial or biaxial nature of objects. In this method, a strong converging polarized beam is illuminated.
(4) Requirements for polarizing microscopes on the device
a. Light source: It is best to use monochromatic light, because the speed of light, refractive index, and interference phenomena are different due to different wavelengths. Ordinary light can be used for general microscopy.
b. Eyepiece: An eyepiece with crosshairs is required.
c. Condenser: In order to obtain parallel polarized light, a swing-out condenser that can push out the upper lens should be used.
d. Bertrand lens: an auxiliary component in the optical path of the condenser, which is an auxiliary lens that magnifies all primary phases caused by the object into secondary phases. It ensures that the oculars are used to observe the planar pattern formed in the rear focal plane of the objective lens.
(5) Requirements for polarized microscopy
a. The center of the stage is coaxial with the optical axis.
b. The polarizer and analyzer should be in an orthogonal position.
c. The tablet should not be too thin.
