Limits of enhancement of the Faraday effect in ultra-thin magnetic layers by one-dimensional magnetophotonic crystals

The optimization of the linear, first-order, Faraday effect in absorbing, ultra-thin, magnetic films is considered both analytically and by numerical simulations. Enhancement using one-dimensional magnetophotonic crystals is considered in parallel with a discussion of the principles of enhancement through an appreciation of the optical resonances that occur in the Fabry-Perot etalon. Simple formulae are presented for the approximate upper limits of enhancement and the associated photometric parameters of the system that accompany optimal conditions. For a 1 nm thick cobalt layer the degree of enhancement is approximately a factor of 4 greater than can be achieved with a single layer. The validity of the formulations is confirmed by numerical simulations based on the use of cobalt as the magnetic medium