Image rotating diffraction grating

In a diffraction grating formed from a stripe-domain supporting magnetizable film, the method of establishing the inter-domain walls in a radially directed orientation and their separation proportional to the distance from the center of the diffraction grating comprising:

• orienting an orienting field coil, having an iron core of substantially zero magnetic remanence, substantially orthoganal to, and above the planar surface of a stripe-domain supporting magnetizable film;
• orienting a tickle field coil, having an air core, substantially parallel to the planar surface of the stripe-domain supporting magnetizable films;
• energizing said tickle field coil by an AC drive current signal of significant to decreasing to zero amplitude;
• and,
• concurrently energizing said orienting field coil by a pulsed drive current signal that extends beyond the termination of the AC drive current signal, said energized tickle field coil and orienting field coil inducing in said stripe-domain supporting magnetizable film fields that conjointly establish the inter-domain walls in said film in a radially directed orientation, the separation of which is proportional to the distance from the center of the diffraction grating.