According to one aspect, systems and methods are provided for detecting the relative position of a transducer head with respect to a storage medium utilizing optically diffractive media. In one example, a head positioning servo system includes a transducer head assembly, a diffractive medium spatially fixed with respect to the transducer head assembly, a light source for illuminating at least a portion of a magnetic storage medium and the diffractive medium, a detector for detecting light from the light source illuminating the magnetic storage medium and the diffractive medium, and a controller for adjusting the position of the transducer head with respect to the magnetic storage medium in response to the detected light.