Transmittivity And Response Time Of The Magnetic Fluid Under Applied Field

Nano-magnetic fluid is a kind of colloid consist of nano-structured ferromagnetic particles disperse in the carrier liquid by means of surfactant. It is a novel functional material in optical field, which has both the fluidity of liquid and the tunable optical properties. There are so many literatures about the aspects of optical switch, tunable fiber modulator and filter. In the interest of enhance the response time of the device that based on the magnetic fluid result in the research of this dissertation.The response time and transmittivity of magnetic fluid under different conditions controlled by magnetic field were investigated in this treatise, experimental results show that response time and transmittivity are variable with the change of the temperature, concentration, and magnitude of field, response time at the level of millisecond, and ascending firstly then katabatic with the enhance of concentration and temperature. However, response time degressive with boosting of field.Compared with the electromagnet used before, the response time of the electromagnet made by ourselves now is decreased from 300ms to 40ms, in this case, the time measured by us should be more precise. Due to the dichroism, the polarized direction of the light also have influence on the transmittivity, experiments are done to study the parallel and perpendicular to the magnetic field dependent the transmission of the light, we obtained the two transmitted curves are distinguished between the magnitude and shape. Doping by SiO2 also have influence on the transmittivity. As for paraffin-based magnetic fluid, the more doped, advent of the point which abruptly ascend correspond to smaller field towards the ordinary ray, whereas for the extrodinary ray, transmittivity increase with the impurity. Furthermore, variation of the optical intensity versus doped mass percent of water-based magnetic fluid is depicted, from the result of the experiment we obtain that variation of optical intensity decrease with impurity, vice versa, the extent of impurity can be estimate by brightness of the ray.