Comparing the Light and Electron Microscope

Comparison between optical microscope and electron microscope In this article, we compare the optical microscope and the electron microscope and see the advantages and disadvantages of each microscope, to see if one is superior to the other. Well-known optical microscopes or optical microscopes were invented in the 17th century and have been improved in various ways for many years, but they remain essentially the same. The operating principle of the optical microscope, the light from the light source under the stage passes through the glass lens in series.

SEM represents a scanning electron microscope. Electron microscopes use electrons for imaging just as optical microscopes use visible light. The SEM uses a specific set of coils to scan the beam in a raster pattern and forms an image using electrons that reflect or collide with the near surface region of the sample. Since the wavelength of the electrons is much smaller than the wavelength of the light, the resolution of the SEM is superior to the resolution of the optical microscope. Let's focus on SEM. A schematic diagram of the SEM technique is shown in FIG. 1 below. In this type of electron microscope, the electron beam scans the sample in a raster pattern. But first, the electron source generates electrons on the electron source. They are released when their thermal energy overcomes the work function of the source material. Then they are accelerated and drawn by the positively charged anode

There are two types of electron microscope: scanning electron microscope and transmission electron microscope. However, since transmission electron microscopes provide higher resolution than scanning electron microscopes, they are preferred in terms of structural biology. In TEM, two kinds of electron sources are generally used. These include hot electron guns and field emission guns. In hot electron guns, electrons are emitted from heated wires such as bent tungsten or sharp lanthanum hexaboride crystals which are emitted by a sharp pointed cathode through a string electric field with a field emission gun.