Improved sensitivity in novel scheme of magneto-optical field sensor

The sensitivity of magnetooptical detection of small fields with multidomain materials under a coherent light is discussed. For fields below the saturation, a novel scheme is proposed to increase sensitivity. Separate detection of the undeflected zeroth-order beam and diffracted beams enables their opposing responses to be added. A garnet of θ_F=60° (where _F is the saturation Faraday rotation) yielded a high sensitivity of more than twice that in the conventional optical configuration while a material of θ_F=90° offers a theoretical improvement of a factor of four