Write head with a micro coil for magneto-optical data storage

To increase storage capacity, an advanced magneto-optical recording technology using high numerical aperture (NA) optics (NA>0.8) in combination with a micro coil creating a local magnetizing field has been investigated. For data recording, a beam of blue laser light locally heats up the magneto-optical storage layer, which is then magnetized by the micro coil. The micro coil therefore needs to be located at a very small working distance (<50 μm) from the disks, which requires the magnetic coil to be mounted between the lens and the disk. Furthermore, the substrate has to be transparent to allow the laser beam to pass through the center of the magnetizing coil. The microcoil that has been developed has proven capable of creating the magnetic field required for magneto-optical recording, could operate at the required recording frequencies, and promises sufficient heat dissipation.