Design, fabrication, and performance of enhanced magneto-optic quadrilayers with controllable ellipticity

An outline is given of a technique for designing quadrilayers that enhance the magneto-optic polar Kerr effect by maximizing the signal-to-noise ratio associated with readout systems utilizing differential detection. The method is particularly novel in that it produces maximized Kerr rotations with controllable ellipticities by using a systematic design procedure that does not involve computer-driven iterative techniques that search for optimum film structures. A number of quadrilayers, based on the ZnS-TbFeCo-ZnS-Al system, have been prepared using rf and dc sputtering and conventional evaporation techniques. The performance of the devices in terms of the basic optical and magneto-optical functions is good compared with theoretical predictions, both at the design wavelength and at all other regions of the spectrum, in the range 400-800 nm.