Fabrication and Properties of Spatial Light Modulator with Magneto-Optical Faraday effect

摘要

This paper represents fabrication and properties of an improved current-driven 128 by 128 magneto-optic spatial light modulator (MOSLM) consists of arrayed pixels patterned with 14 micrometers square of 16 micrometers pitch. It could be driven successively only drivelines without a bias field by external coil to saturate magnetization. The magnetic pixels were embedded into the nonmagnetic substrate both to avoid magnetic switching error and to make the pixels array surface smooth. The switching field of arrayed pixels was reduced to 145Oe by annealing them to decrease the growth induced magnetic anisotropy. This value was about half of the conventional 128 by 128 MOSLMs. Moreover, copper straight drivelines were used for decreasing electric power consumption and applying a homogeneous magnetic field to the pixel. This drivelines structure enabled to switch the individual pixels reversibly keeping a single domain state, therefore, the successive driving of writing and erasing various checker patterns could be possible without bias field by external coil. The electric power consumption was decreased about 70%. The switching speed of one pixel was 25 nanoseconds. It is more than a thousand times faster than other types of SLM, for example, 10 to 30 milliseconds for liquid crystal (LC) type, and 10-20 microseconds for micro electro mechanical systems (MEMS) type.