Experimental investigation of magnetically induced unusual emission of light from a ferrodispersion.

An unusual emission of light is observed when a coherent light beam is passed through a mixture of a magnetorheological suspension and a ferrofluid that is subjected to a critical magnetic field. When first the incident light is removed and then the field is switched off, a flash of light is observed. In this Letter certain characteristics of this unusual emission are reported. Our findings suggest that a part of the incident light energy is magnetically trapped within the medium. Upon removal of the field, the same is released. Several physical phenomena that may give rise to such emission are discussed. The magnetically tunable emission will be useful to develop photonic devices.