[Zurück]

M. Battiato, G. Barbalinardo, P.M. Oppeneer:
"Quantum theory of the inverse Faraday effect";
Physical Review B, 89 (2014), 014413.

We provide a quantum theoretical description of the magnetic polarization induced by intense circularly
polarized light in a material. Such effect-commonly referred to as the inverse Faraday effect-is treated
using beyond-linear response theory, considering the applied electromagnetic field as external perturbation. An
analytical time-dependent solution of the Liouville-von Neumann equation to second order is obtained for the
density matrix and used to derive expressions for the optomagnetic polarization. Two distinct cases are treated,
the long-time adiabatic limit of polarization imparted by continuous wave irradiation, and the full temporal shape
of the transient magnetic polarization induced by a short laser pulse.We further derive expressions for the Verdet
constants for the inverse, optomagnetic Faraday effect and for the conventional, magneto-optical Faraday effect
and show that they are in general different. Additionally, we derive expressions for the Faraday and inverse
Faraday effects within the Drude-Lorentz theory and demonstrate that their equality does not hold in general,
but only for dissipationless media. As an example, we perform initial quantum mechanical calculations of the
two Verdet constants for a hydrogenlike atom and we extract the trends. We observe that one reason for a large
inverse Faraday effect in heavy atoms is the spatial extension of the wave functions rather than the spin-orbit
interaction, which nonetheless contributes positively.

http://dx.doi.org/10.1103/PhysRevB.89.014413