Spatially inhomogeneous inverse Faraday effect provides tunable nonthermal excitation of exchange dominated spin waves

TL;DR

This paper demonstrates a nonthermal optical method to excite and control exchange spin waves in a magnetophotonic crystal by tuning the interference pattern of the inverse Faraday effect through wavelength variation.

Contribution

It introduces a novel approach to selectively excite spin waves using spatially inhomogeneous inverse Faraday effect in a magnetophotonic crystal, enabling tunable control.

Findings

Phase slippage of inverse Faraday effect within the photonic band gap.

Wavelength variation modulates excitation efficiency of spin wave orders.

Potential for expanding spin-wave device applications.

Abstract

We demonstrate optical nonthermal excitation of exchange dominated spin waves of different orders in a magnetophotonic crystal. The magnetophotonic structure consists of a thin magnetic film and a Bragg stack of nonmagnetic layers to provide a proper nonuniform interference pattern of the inverse Faraday effect induced by light in the magnetic layer. We found a phenomenon of the pronounced phase slippage of the inverse Faraday effect distribution when the pump wavelength is within the photonic band gap of the structure. It allows to tune the interference pattern by a slight variation of light wavelength which results in the modification of excitation efficiency of the different order spin waves. The approach can be applied for different magnetic dielectrics expanding their application horizons for spin-wave based devices.