It is widely known that the magneto-optical Faraday effect is linear in
magnetization and therefore the Faraday angles for the states with opposite
magnetizations are of opposite sign but equal in modulus. Here we
experimentally study propagation of light through a one-dimensional all-garnet
magnetophotonic crystal to demonstrate an asymmetric Faraday effect (AFE) for
which Faraday angles for opposite magnetic states differ not only in sign but
in the absolute value as well. AFE appears in the vicinity of the cavity
resonance for an oblique incidence of light which plane of polarization is
inclined to the incidence plane. Under proper incidence and polarization angles
the magnitude of AFE could be very large reaching 30% of the absolute value of
the Faraday effect. The effect originates from the difference in Q-factors for
p- and s- polarized cavity modes that breaks the symmetry between the two
opposite directions of polarization rotation. The discovered AFE is of prime
importance for nanoscale magnonics and optomagnetism.Comment: Supplementary information provided after the main tex