9/21/2023 0 Comments Faraday isolator schemeThe linearly polarized wave can be seen as a superposition of the two above mentioned circularly polarized components, LCP and RCP. Let’s suppose a linearly polarized light passing through a medium formed by free electrons and fixed positive centres, distributed in such a way to fulfil the local condition of charge neutrality. On the other hand, an elliptically polarized light can be seen as a superposition of two linearly polarized components which are out of phase and with different amplitudes (if the electric fields of the two components are equal, the resulting light is circularly polarized). It can be proven that any linearly polarized wave can be seen as a superposition of two circularly polarized components, namely a left-circularly polarized (LCP) and a right-circularly polarized (RCP) one, of amplitudes E L =E R =E/2. In an elliptically polarized light, the electric field rotates during the propagation, describing an ellipse in a plane perpendicular to the propagation direction (when a circle is described, the wave is called circularly polarized). A linear polarized light is a wave with the electric field vector, E, oscillating along a given direction, perpendicular to the propagation direction (sometimes, this kind of polarization is called plane polarization, the plane of polarization being the plane defined by the direction of the electric field and the direction of propagation). Accordingly, the light is a transverse electromagnetic wave which can be linearly or elliptically/circularly polarized. Theory of Magneto-Optic Phenomena Polarization is one of the most known phenomena supporting the wave character of light. Nowadays, crystals showing large magneto-optical effects are widely used in optical isolators (Faraday rotators, optical circulators), mode-conversion waveguides and optical data storage. The MOKE offers a unique tool for the determination of the surface magnetization of thin films with even higher sensitivity then the Superconducting Quantum Interferometer Devices (SQUID). In addition, the Faraday Effect, and its counterpart in reflection, the Magneto-Optical Kerr Effect (MOKE), are widely used to detect the magnetization of materials. Moreover, it initiated a research for materials showing optical cross effects, in which the fast manipulation of the light beam in sense of its intensity or its polarization can be realized via external fields. This experiment was among the firsts, which indicated the intimate relationship between the magnetic field and the light. In 1845 Michael Faraday discovered that the polarization of a linearly polarized light beam is rotated upon propagating through a media which is placed in a magnetic field parallel to the propagation direction. These effects played an important role in the early history of electromagnetism, providing an experimental support to the electromagnetic theory of light, as well as to both classical and quantum theory of matter including the motions of electron spin and spin-orbit coupling. Such interaction between electromagnetic radiation and magnetically polarized materials results in ‘Magneto-Optic’ effects. Introduction The interaction of light with matter is affected by the magnetic state of the medium and involves the electronic structure of the matter. Relevant theoretical characteristics of these effects and its application in modern technology are also discussed.ġ. This study primarily focuses on the understanding of the mechanism of magneto-optic effect by reviewing and critically discussing the rotation of plane of polarization of the light beam as it is transmitted through a magnetized sample, i.e., the Faraday Effect and the rotation of the plane of polarization of a light beam during reflection from a magnetized sample, namely, the Kerr Effect. Michael Faraday was at the forefront of discovering this phenomenon, as in 1845 he showed that light interacts with magnetic fields. The discovery of magneto-optical effects evoked a new thought that the nature of light was an electromagnetic entity, and played a central role in the contribution of the development of Maxwell's electromagnetic theory. The research activities on the phenomenon of Magneto-optic Effects has recently promulgated due to its versatile use in magneto-optic recordings for high density magnetic data storage, magnetic field sensors and its applications in magneto-electronics.
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