偏光显微镜的工作原理
Polarized light microscopy is a technique that relies on the polarization of light to analyze and visualize microscopic objects. A polarizing light microscope is an optical instrument used to study the microscopic structure of a sample. The polarizing microscope uses polarized light, which has been split in two parts, each with a different orientation, to achieve its precise imaging properties.
In a polarized light microscope, light is passed through a polarizing filter, usually made of a quartz or birefringent crystal. The filter splits the light into two parts called polarizations. One polarization is parallel to the plane of the filter and the other is perpendicular. When the light passes through the sample, it will be either transmitted or absorbed. Depending on the orientation of the sample, different kinds of light waves will interact with it, resulting in certain conditions that create tiny variations in the incident beams path.
These variations create two images: one bright and one dark. The bright image represents the light-transmission properties of the sample, while the dark image represents its light-absorption properties. The combination of these two images creates an enhanced contrast that allows the user to observe the sample in greater detail.
In polarized light microscopy, the polarizer passes through two stages. In the first stage, the sample is inserted between two polarizers and the two polarizations are adjusted accordingly. The light then passes through the sample and is directed towards a set of analyzers (also known as analyzer or retarder) that further manipulate the light before it is projected onto a photographic plate or into an eye-piece.
The analyzer consists of two optically active elements, a quarter wave plate and a half wave plate, which control the direction and intensity of the polarization of the light. The quarter wave plate rotates the polarization of light and induces diraction, which creates interference patterns that are used to examine the sample. The half wave plate alters the light’s intensity, causing interference that allows for the visualization of different structures within the sample.
Polarized light microscopy is used in various applications, including optical chemistry and pathology. In optical chemistry, the technique is used to identify and analyze the composition of chemical components in a sample, while in pathology, it is used in conjunction with other methods to identify diseases and their patterns.
In addition to its research applications, polarized light microscopy is also used in various industrial and manufacturing fields. In the production of metals, for example, the technique is used to measure the texture and surface topography of a metal. It is also used to assess the quality of certain kinds of glass, as well as in the inspection of food products such as dairy and dairy products. Lastly, the technique is used to test the reliability of electronics, assess the welding of metal parts, and confirm the quality of polymers and plastics.
In summary, polarized light microscopy is a powerful technique for visualizing and examining microscopic objects. By manipulating the polarized light, this technique is capable of providing highly detailed images, which can be invaluable for researchers and industrialists alike. The versatility of the technique makes it applicable in a wide range of fields and its ongoing development has ensured that it remains an invaluable resource for many industries.
