Magnetoplasmonic Crystals for Highly Sensitive Magnetometry

Abstract

Magnetometry and visualization of very small magnetic fields are vital for a large variety of the areas ranging from magnetocardiography and encephalography to nondistractive defectoscopy and ultra-low-frequency communications. It is very advantageous to measure magnetic fields using exchange-coupled spins in magnetically ordered media (flux-gate magnetometry).Here we introduce and demonstrate a novel concept of a roomtemperature magnetoplasmonic magnetic field sensor with high sensitivity and spatial resolution. It is based on the advanced fluxgate technique in which magnetization of the fully saturated magnetic film is rotated in the film plane and the monitored magnetic field is measured by detecting variation of transmittance through the sensing element: a magnetoplasmonic crystal. The experimental study revealed that such an approach allows one to reach the nT sensitivity level, which was limited by the noise of the laser. Moreover, we propose an approach to improve the sensitivity up to fT/Hz 1/2 and reach micrometer spatial resolution. Therefore, the demonstrated magnetoplasmonic magnetometry method is promising for mapping and visualization of ultrasmall magnetic fields.

All-dielectric magnetic metasurface for advanced light control in dual polarizations combined with high-Q resonances

“…Light modulation by magnetic field has been successfully used for various practical applications such as magneto-optical modulators, isolators, routers and other non-reciprocal devices 1 – 8 , magneto-optical biosensors 9 – 14 as well as magnetometers 15 – 18 . For all of the named areas, it is important, on the one hand, to increase the magneto-optical performance of the nanostructure, and on the other hand, to achieve miniaturization of the device and make it compatible with integrated optics.…”

Magnetically controllable metasurface and its application

“…It is worth noting that Faraday effect has a unique property of breaking the time-reversal symmetry and Lorentz reciprocity, making it applicable to various nonreciprocal devices, such as isolators and circulators. MO metasurfaces based on Faraday and Kerr effects have been widely used in various fields, such as chiral sensing [14], biochemical sensing [15], magnetic field sensing [16], MO storage [17], and MO switch [18]. However, it is challenging to make the nanoscale metasurface achieve a strong response due to the weak effect of the MO material.…”

Broad band infrared modulation using spintronic-plasmonic metasurfaces

“…Phase-change materials as VO 2 also exhibit a change in their optical response, namely an insulator-to-metal transition, which can be driven by either heating the sample or using external laser pump pulses [11]. This change in the permittivity can be exploited, among other uses, for increasing the sensitivity of optical sensors [12][13][14][15], creating switching mono/bi-directional devices [16,17] or fabricating other active infrared devices [18][19][20]. Recently, the family of the giant magnetoresistance (GMR) materials is incorporated into the list of active-control opportunities, demonstrating modulation of mid-infrared response in spintronic-plasmonic platforms using very low magnetic fields [21,22].…”