ABSTRACT
Particle property of light is manifested only in the case of energy interaction between electromagnetic waves and matter. In general, light is classified in terms of wavelength. We can discuss all phenomena, including the propagation of radio waves, imaging of visible light and X-ray diffraction, in a unified manner. The principle of superposition is one of the most fundamental principles in wave physics, which is due to the linearity of the wave equation. The wave with planar wavefront is called a plane wave. It should be noted that a wave propagates to the direction perpendicular to its wavefront. Generally, the light wave is considered as a scalar wave, but in an inhomogeneous media or near an aperture or boundary of homogeneous media, the components of electric and magnetic fields are not independent and interact with each other. In such a case, the scalar approximation is not valid and the light wave should be considered as a vector wave.
