Why can't you see smaller things with an optical microscope?
A microscope is an optical instrument composed of a lens or a combination of several lenses, which can magnify tiny objects into images that people can see with the naked eye. Since the invention of the microscope in the 17th century, it has provided a powerful aid to biologists and medical scientists in discovering bacteria and microorganisms. Today's optical microscopes can magnify objects up to 1500 times, and even very tiny cells, bacteria, viruses and other objects can be clearly seen under the microscope.
However, the seemingly powerful optical microscope also has its limits. Because the microscopic world is infinite, very small matter also has smaller components, and optical microscopes can only see things larger than 0.2 microns. If it wants to observe something smaller, it can't do anything about it. Why is this?
It turns out that light is also a kind of wave, and its wavelength is 0.4 microns. If it encounters something smaller than half its wavelength during the propagation process, it will bypass it directly. This condition is called diffraction of light. Under an optical microscope, once the light is diffracted, the light will become some very small circles or arcs, and we can only see a few blurred spots, but not the specific outline of the object. Because of this, optical microscopes have remained largely unchanged since the 19th century.
