Magneto-Optics: Electrically Adressable Integrated Magneto-Optical Functional Structures

Magneto-optical active materials turn the polarization direction of linear polarized light when a magnetic field is present. Typically, these materials are represented by iron garnets. Bi3Fe5O12 represents the alloy having the highest degree of Faraday rotation at room temperature. Presently, the magneto-optical active garnets are merely deposited on substrates which likewise have a garnet structure (e.g. Gd3Ga5O12). To make their properties accessible as a new function to microelectro mechanical systems or to integrated optics it is required to integrate them on Si or SiO2 , which is the intention of this project. Combining those different materials poses a particular challenge. The integration of Bi3Fe5O12 on Si/SiO2 can only be realized via a Y3Fe5O12 buffer layer, which leads to interference effects and thus to an enhanced Faraday rotation during light transmission.

With the aid of combinatorics double layers of garnet materials with different degrees of doping will be integrated on Si or SiO2 for the first time. Further, the interference effect will be examined. Another objective of this project is to elucidate the integration process of the garnet double layers on Si or SiO2 by means of extensive structural examinations. By manipulating the Faraday effect occurring in the garnets a magneto-optical switching element could be realized. For this purpose, the influence of acoustic surface waves on the Faraday rotation is to be examined.