Magnetic rotation of the plane of polarisation of extremely short pulses in equilibrium and nonequilibrium media

A theoretical investigation is reported of the Faraday rotation of the plane of polarisation of extremely short broad-band optical pulses. It is shown that in thermodynamically equilibrium and weakly nonequilibrium media, when steady-state propagation of such pulses is possible, the angle of the paramagnetic rotation per unit length for extremely short pulses is the same as for a high-frequency plane linear wave. In strongly nonequilibrium (amplifying) media the Faraday rotation is again uniform during the propagation of a signal, but the angle of rotation differs from that for a high-frequency linear wave.