Magneto-optical plasmonic Bi:YIG composite films with Ag and Au-Ag alloy particles

Abstract

To obtain enhancement and wavelength tuning of the magneto-optical (MO) response associated with the localized surface plasmon resonance (LSPR), bismuth-substituted yttrium iron garnet (Bi:YIG) composite films with Ag particles and Au-Ag alloy particles were studied. The Bi:YIG composite film with Ag particles did not show any enhancement of Faraday rotation. On the contrary, the Bi:YIG composite films with Au-Ag particles exhibited the enhancement of the MO response for different wavelengths of LSPR. We observed the enhanced Faraday rotation for the Bi:YIG/Au-Ag composite films with volume ratios of Ag up to 0.6. In addition, when changing the volume ratio of Ag, the peak of rotation shifted to short wavelengths. Disappearance of enhancement for the Bi:YIG/Ag composite film can be addressed to modifying the interfacial medium between the MO host and Ag. Since chemically active Ag particles can form nonmagnetic Ag compound shells separating Bi:YIG and the plasmonic subsystem, the LSPR of Ag particles did not affect the MO response. The Au-Ag alloy particles were chemically stable in the Bi:YIG/Au-Ag composite films.

Peculiarities of plasmon-modified magneto-optical response of gold–garnet structures

“…The inherent Faraday rotation of Bi:YIG both increased or decreased the magnitude of the polarization rotation of the nonmagnetized Au-Bi:YIG sample [see dashed lines in plots (a) and (b)]. The resulting single-pass spectrum θH had a peak, illustrating MO enhancement as discussed in previous publications [16,17,25]. One can speculate that magnetization of Bi:YIG brings an additional lever for the cumulative polarization rotation, because plasmonic Au, with its inherent transmission anisotropy, may act as a sensory system for the MO background.…”

“…Surface plasmon-affected magneto-optical (MO) responses from various plasmonic structures have been studied, demonstrating modified spectra of conventional MO films [1][2][3][4][5][6][7][8][9][10], composites [11][12][13][14][15][16][17][18], and periodical structures [19][20][21][22][23][24][25][26][27][28]. Such a plasmonic MO material possesses LSPR-related features in the Faraday (or Kerr) rotation spectra, where the enhanced polarization rotation is accompanied by a strong light absorption of radiation by the noble metal subsystem; see [16,17] for examples.…”

“…Such a plasmonic MO material possesses LSPR-related features in the Faraday (or Kerr) rotation spectra, where the enhanced polarization rotation is accompanied by a strong light absorption of radiation by the noble metal subsystem; see [16,17] for examples.…”

Garnet composite films with Au particles fabricated by repetitive formation for enhancement of Faraday effect

“…Then, with Au particles embedded in Bi : YIG thin films on quartz substrates [11] large enhancement of Faraday rotation was observed. Later the use of Au-Ag alloy particles in composite films was attempted to shift the LSPR wavelength for enhanced Faraday rotation by changing the composition ratio [12].…”

Вертикальное Смещение Магнитооптической Петли Гистерезиса В Магнитоплазмонном Нанокомпозите

“…Подобные магнитоплазмонные системы неоднократно рассматривались различными авторами, в том числе и авторами данной работы [5][6][7][8]. При этом отмечалось, что на длине волны света, соответствующей частоте резонанса плазмонной подсистемы, наблюдается существенное усиление МО-эффекта Фарадея.…”