Optical Microscopy - How it works

Modern microscopes, which, unlike the electronic will be called the optical, are perfect devices, allowing to obtain high magnification with high resolution. Resolution is determined by the distance at which two adjacent elements of the structure can still be seen separately. However, studies have shown that optical microscopy has almost reached the principal limit of their capacity due to diffraction and interference phenomena due to the wave nature of light.

The degree of coherence of monochromatic and is an important characteristic of waves of any nature (electromagnetic, sound, etc.). Monochromatic variations are oscillations, consisting of sine waves of one particular frequency. When we introduce variations in the form of a simple sinusoid, respectively, with constant amplitude, frequency and phase, it is a certain idealization, because, strictly speaking, in nature there are no vibrations and waves, exactly described by a sine wave. However, studies have shown that the real Waves may, with greater or lesser degree of accuracy close to the ideal sinusoid (have more or less monochromatic). Oscillations and waves of complex form can be represented as a set of sinusoidal oscillations and waves. In fact, this mathematical operation provides a prism is expanded into a color spectrum of sunlight.

Monochromatic waves, including light, the same frequency (under certain conditions!) Can interact with each other so that the resulting "light turned into darkness," or, as they say, the waves can interfere. During the interference occurs local "gain and suppression of the waves with each other. In order to wave interference pattern has remained unchanged over time (for example, by looking at her eye, or photography), it is necessary that the waves were coherent with each other (two waves are coherent with each other, if they give a stable interference pattern, which corresponds to the equality of their frequencies and constant phase shift).
If on the path of wave propagation are placed obstacles, they will significantly influence the direction of propagation of these waves. Such obstacles may be the edge of holes in the screens, opaque objects, as well as any other types of irregularities in the way of propagation. In particular, the heterogeneity may also be transparent (for a given radiation) objects, but differ on refractive index, and hence the velocity wave propagation within them. The phenomenon of changing the direction of wave propagation passing near their obstacles called diffraction. Usually diffraction is accompanied by diffraction interference phenomena.

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