We report enhanced optical Faraday rotation in gold-coated maghemite (gamma-Fe(2)O(3)) nanoparticles. The Faraday rotation spectrum measured from 480-690 nm shows a peak at about 530 nm, not present in either uncoated maghemite nanoparticles or solid gold nanoparticles. This peak corresponds to an intrinsic electronic transition in the maghemite nanoparticles and is consistent with a near-field enhancement of Faraday rotation resulting from the spectral overlap of the surface plasmon resonance in the gold with the electronic transition in maghemite. This demonstration of surface plasmon resonance-enhanced magneto-optics (SuPREMO) in a composite magnetic/plasmonic nanosystem may enable design of nanostructures for remote sensing and imaging of magnetic fields and for miniaturized magneto-optical devices.
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http://dx.doi.org/10.1021/nl900007k | DOI Listing |
Sensors (Basel)
January 2025
Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 109, Acad. G. Bonchev Str., 1113 Sofia, Bulgaria.
Magneto-optical magnetic field/current sensors are based on the Faraday effect, which involves changing the polarized state of light. Polarimetric methods are therefore used for measuring polarization characteristics. Channeled polarimetry allows polarization information to be obtained from the analysis of the spectral domain.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2G2.
Rigid, conjugated molecules are excellent candidates as molecular wires since they can achieve full extension between electrodes while maintaining conjugation. Molecular design can be used to minimize the accessible pi surface and interactions between the bridging wire and the electrode. Polyynes are archetypal molecular wires that feature a rigid molecular framework with a cross-section of a single carbon atom.
View Article and Find Full Text PDFTuneable, variable, optical attenuation through an optical circulator with a broad, linear attenuation range of Δ ∼ (30-40) dB is demonstrated using non-reciprocal Faraday rotation in a double-pass configuration with a combination of permanent magnets and an electromagnet. A fiber-coupled magneto-optical variable optical attenuator (MVOA) operates over the near IR with an attenuation tuning range of Δ > 30 dB, a resolution of Δ ∼ 0.02 dB, a response time of < 2 ms, and a temperature dependence over = 25-70°C of Δ / Δ = -8 × 10 dB/°C.
View Article and Find Full Text PDFWe study experimentally the nonlinear mode coupling between circular polarizations in a vertical-cavity surface-emitting laser (VCSEL) device developed for spin injection. The specific experimental arrangement that includes a Faraday rotator enables laser oscillation on left-circular or right-circular polarization, by adjusting the cavity losses. We show the simultaneous oscillation of both polarizations never occurs, proving that the Lamb coupling constant is very close to 1 in this VCSEL device, a situation that is ideal for spintronic applications.
View Article and Find Full Text PDFTo design an innovative magneto-optical material aimed at a large Verdet constant coincides with the development trend of state-of-the-art modern optical devices. In this work, a magneto-optical transparent PrZrO ceramic with pyrochlore structure was successfully fabricated by vacuum sintering plus hydrogen reduction for the first time to our knowledge. The two- and three-dimensional images observed on the laser scanning confocal microscopy reveal that the grain-boundary dent depth of the polished PrZrO ceramic is only ∼1.
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