wave nature of light has been proved long ago.In order to solve practical problems often use the principles of geometrical optics, and wave properties of light is very widely used in various branches of modern science and technology.An example of this is diffraction.The ability of waves to bend around obstacles encountered in its path, and the inherent light.This phenomenon occurs when the waves fall within the so-called geometric shadow.Explain the phenomenon of diffraction gives the principle of Huygens.According to the explanation of each point, encountered by the wave, it became the center for the secondary waves.The envelope of these waves is given by the position of the wavefront for each of the following points in time.
In the example of a plane wave normally incident on the hole made in an opaque screen, on the theory of Huygens, every point of which is designated the opening portion of the wavefront, inherent ability to become a source of secondary waves (in a homogeneous isotropic medium are spherical).
sufficient to construct the envelope of the secondary waves at a point in time to easily trace the phenomenon of diffraction wave edge of the hole.This is due to the fact that the wavefront enters the area of so-called geometrical shadow.
Using the properties of diffraction is widely used in the device, called a diffraction grating.In their initial experiments with diffraction of light James Gregory used the usual feather.Later, he was replaced by a specific optical device.The diffraction grating is deposited on the surface of a certain set of a significant number of strokes, arranged regularly.They can be both slits and protrusions, depending on the species to which the particular grating.
are two types of arrays - reflective and transparent.The former include appliances that use a reflective surface with applied strokes.The second uses the transparent surface here can be used as strokes and gap.
principle of action is due to the diffraction grating directly wave properties of light.To break the light wave front grille used strokes.This produces the so-called individual beams of coherent light.Having undergone diffraction by touch, they interfere with each other.Given the fact that different wavelengths to create a maximum of interference from a completely different angle (defined path difference of interfering beams) is produced at the output expansions in the range of white light.
diffraction grating as the device is used in various spheres of human activity.It is used in spectral devices, and as optical angular sensors (linear) movement and as polarizers or filters infrared radiation.Also, it may be for the interferometer beam splitter glass or "anti-reflective" points.
There is a diffraction grating for X-rays.Create it turned out to be technically impossible task.To solve this problem scientists have gone the original way.For the decomposition of X-rays used crystal lattices of certain crystals.
As the main characteristic considered the resolution of the diffraction grating.It represents the total number of lines in the grating, which is multiplied by the order of the maximum beam.This expression can still be present as an assertion that is characteristic for the frequency difference equal to the reciprocal of the difference in time periods pass the most extreme rays referred to as interfering.
in life a good example of the diffraction grating can serve as a CD or phonograph record.But for the manufacture of industrial equipment used high-tech equipment with high precision.
