Research Magnetostrictive Stress-induced Birefringence

Magneto-optical effect can be used to control the optical intensity, phase, direction of polarization and propagation of the transmission light wave, which is broadly used in magneto-optic modulator, magneto-optical switch, magneto-optic isolator and etc.. More than a century has passed since Voigt and Cotton-Mouton observed the phenomenon of magneto-birefringence (MBR) in gas and liquid, respectively. However, the rapid development of composites, especially the laminate solid composites, supplies us the possibility of observing Magneto-optical effect in solid. The working principle of Magneto-optic transducer in optical fiber teaches us that magneto-optical effect can be produced in composition of GMM and optical material.The thesis introduced the new composite material which is consisted of TDF and PC using the Stress Coupling principle. We adopt the structure of three layers flat which can reduce the influence of stress gradient inside of the composite material. The laminated composite has simple structure, and is easy to prepare, which breaks a new path for developing high performance magneto-optical material and provides a new thinking for material selection. The composite material has taken advantage of the product effect of magnetostrictive effect and stress birefringence effect, so we can get better result by choosing proper material, and the composite material above may have vast potential for future development in the area of modulator and transducer.There are lots of impact factors for property of layered magneto-optical composites, such as the performances of magnetostrictive phase and stress birefringence phase, volume fraction and interface coupling, so it does require building a theoretical model for the study of property and variety regulation. We proceed from the constitutive equations of magnetostrictive and stress birefringence phase, and use elastic mechanics models to derive the formulation of normalizing transmitted intensity which is up to the material’s size and property, and in this course, St. Venant principle is used in calculating the stress distribution inside the stress birefringence phase. According to the theoretical result, we discuss the contributing factors such as width d2and thick-length ratio d3/d1of stress birefringence and wave length λ of the laser. The experiment results show that bigger width and smaller thick-length ratio provide higher performance, and proper wave length λ and upstanding interfacial coupling are also crucial factors for a perfect experiment result.The experiment result matches the theoretical result well. However, we have minor flaws in the size of materials used and production process which are waiting to be solved or improved. In addition, the thesis discusses the sample result in direct magnetic field, and I suppose that experiment in AC magnetic field may lead a important result which has some important implications in development of magneto-optical devices.