Time-resolved measurements of the magnetism induced by the inverse Faraday effect in non-magnetic metals*

The inverse Faraday effect is an optomagnetic phenomenon that describes the ability of circularly polarized light to induce magnetism in solids.  The inverse Faraday effect has potential applications for the development of magnetic recording, quantum computation and spintronic technologies. However, significant gaps in understanding about the effect persist, such as what material properties govern the magnitude of the effect. In this work, we measure by time-resolved magneto-optic Kerr effect measurements of the magnetic moment induced when circularly polarized light irradiates a non-magnetic metal.  We measure this inverse Faraday effect in Cu, Pd, Pt, W, Ta and Au for a laser wavelength of 783 nm. We observe that irradiation of these metals with circularly polarized light induces circular dichroism. This nonlinear magneto-optical response to circularly polarized light is an order of magnitude larger in bcc W than other metals, e.g. Pt, Au, or α-phase W.  Our results provide insight into what material properties govern the inverse Faraday effect in metals.