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

Abstract

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.