Influence of surface plasmons on the Faraday effect in bismuth-substituted yttrium iron garnet films

Abstract

The Kerr rotation and ellipticity of Bi1.8Y1.2Fe5O12 films (Bi:YIG) with the easy axis of magnetization perpendicular to the film plane was investigated in a Kretschmann setup at the wavelength 1.31 μm. The sample was coated by a thin Au film in order to excite plasmons at the free Au surface. An ellipsometric setup, supplemented with a magnetic field oriented perpendicularly to the film plane was used to measure the reflected p and s components of an incoming p polarized wave. The phase difference between the outgoing p and s waves was found by an indirect procedure. A minimum in Kerr rotation and a maximum in Kerr ellipticity could be observed at the surface plasmon resonance angle. Using the Berreman formalism, the experimental curves for the prism/Bi:YIG/Au system could be reproduced by bulk optical constants of the constituents. The asymmetry of the ellipticity curve is demonstrated to arise from a sudden variation in the phase. The effects of the field distribution and the surface roughness are discussed.

Magnetoplasmonics: Combining Magnetic and Plasmonic Functionalities

“…[ 143 ] On the other hand, Kochergin et al [ 144 ] detected an enhancement in the longitudinal MO signal associated with the propagation of a SPP for a Bi-IG grating coated with a Ag/Au multilayer, and subsequently proposed the use of SPP excitation as a tool for resolution increasing in MO imaging of fi lms. In this sense, a preliminary experiment on the infl uence of surface plasmons on the Faraday effect in bismuthcontaining iron garnet (Bi-IG) fi lms coated with a thin fi lm of Au was presented by Bremer et al in ATR geometry.…”

A gigahertz surface magneto-plasmon optical modulator

“…As a result, there are two branches (upper and lower) in the dispersion relation, with an increasing split between the branches as the magnitude of the off-diagonal elements of the permittivity tensor increases. In addition, for large (in the large wavevector limit, ) the dispersion relation for transverse magnetization requires (17) Combining (5) and (17) and assuming a collision-free plasma , the asymptotic limit is given by (18) It is interesting to note that, by setting (no MO interaction), the standard SP frequency at an interface between two isotropic, nonmagnetic media is recovered [29].…”

“…The proposed configuration is unlike previously reported geometries used to study polariton enhancement of the Faraday effect in bismuth-substituted garnets. In these experiments, a light beam propagated through the MO active region and subsequently excited SP waves at a metal surface on the backside of the MO film [17], [18]. Such configurations cannot distinguish between effects such as: Faraday rotation, SP coupling, birefringence, and material absorption.…”

Polar magneto-optical effects in magnetoplasmonic thin films illuminated by attenuated total reflection

“…The transverse magneto-optical Kerr effect under attenuated total reflection conditions has recently drawn widespread interest for the development of active plasmonic devices and optical sensors. 7,8 On the other hand, the enhancement of the magneto-optical activity caused by surface plasmon polariton excitation has been observed under polar magnetic fields, 9,10 and the polar magneto-optical Kerr effect has also attracted considerable attention. In the attenuated total reflection configuration, the Faraday magneto-optical activity of the glass material can modify the light polarization under a polar magnetic field, 11,12 and it also has a negative influence on measurements of the intrinsic magneto-optical responses of the thin films.…”