Giant peak of the Inverse Faraday effect in the band gap of magnetophotonic crystal

TL;DR

This paper demonstrates a significant enhancement of the inverse Faraday effect within the band gap of a magnetophotonic crystal, enabling localized and tunable optical control of magnetization for ultrafast spintronics and quantum applications.

Contribution

It reveals a giant peak of the inverse Faraday effect in the band gap of a magnetophotonic crystal, with strong electromagnetic confinement leading to subwavelength magnetic field localization.

Findings

Spectral peak of IFE in the band gap causes enhancement.

Electromagnetic energy confinement explains the peak.

Localized magnetic fields can be shifted by changing laser wavelength.

Abstract

Optical impact on the spin system in a magnetically ordered medium provides a unique possibility for local manipulation of magnetization at subpicosecond time scales that is very promising for magnetic data processing and other magnonics applications. One of the mechanisms of the optical manipulation is related to the inverse Faraday effect (IFE). Usually the IFE is observed in crystals and magnetic films on a substrate. Here we demonstrate the IFE induced by fs-laser pulses in the magnetic film inside the magnetophotonic crystal. Spectral dependence of the IFE on the laser pulse wavelength in the band gap of the magnetophotonic crystal has a sharp peak leading to a significant enhancement of the IFE. This phenomenon is explained by strong confinement of the electromagnetic energy and angular momentum within the magnetic film. Calculated near field distribution of the IFE effective magnetic field indicates its subwavelength localization within 30 nm along the film thickness. These excited volumes can be shifted along the sample depth via e.g. changing frequency of the laser pulses. The obtained results open a way for the new applications in the areas of ultrafast spintronics and quantum information processing.