Magnetically actuated optical phase modulator

A magnetically actuated optical phase modulator is described. The phase of a reflected optical beam is modulated by deflecting a Mylar® membrane, coated with a magnetic iron/nickel film, with the field of an electromagnet. A phase change of π for light of wavelength 0.633 μm was achieved with a driving voltage of only 4 V, much smaller than the voltage required for comparable, electrostatically-actuated devices. The modulator can be scaled to micron dimensions for fabrication in arrays, scaled for even lower drive voltage, and operated at megahertz frequencies.