Electro-optic beam deflectors for magneto-optic recording heads (abstract)

Abstract

To make magneto-optic recording more competitive for data storage, the access times for the magneto-optic head must be reduced. By incorporating nonmechanical beam deflection into a split head architecture, fine access times can be reduced considerably and tracking robustness can be improved. Track switching times of ∼10 μs have been reported by Arimoto et al. using a surface acoustic wave beam deflector.1 In the present work, the use of electro-optic deflection techniques is discussed and demonstrated. Potential advantages of electro-optic scanners include lower power consumption and higher optical throughput. To demonstrate the use of an electro-optic beam deflector, an optical system using a commercially manufactured electro-optic deflector has been assembled to detect a signal from a magneto-optic sample. In this system, a 488 nm laser beam is sent through the deflector into a microscope which is used to focus the beam onto the medium. As the beam deflector scans a focused spot across a magnetic stripe domain on a thin film medium, the reflected beam is sent through a differential detection system which detects the change in polarization due to the Kerr effect. In this way, the presence of the domain is detected without mechanical motion. Experimental detection of 0.6 μm wide stripes has been demonstrated using this system. We believe similar beam deflectors in thin film form could significantly impact the performance of magneto-optic recording heads.