Design of Nanoarchitectures for Magnetoplasmonic Biosensing with Near-Zero-Transmittance Conditions

Abstract

Nanostructures exhibiting large transverse magnetooptical Kerr effect (TMOKE) are required for magnetoplasmonic biosensing if the aim is the minituarization and integration into microfluidic devices. In this work, we present a general strategy to design nanoarchitectures with enhanced TMOKE, which consist of an arrangement of gold ribs deposited on an magneto-optical (MO) dielectric slab of Bi:YIG (bismuth-substituted yttrium iron garnet) with a SiO 2 substrate surrounded by water. Using the finite element method (FEM), we demonstrate numerically that the near-zero-transmittance condition is the most important requirement for high TMOKE values. This can be reached through geometric optimization of the nanoarchitecture by tuning the period, height, and width of the grating, thus leading to resonances at wavelengths where the MO dielectric slab has high MO activity. We also show that the TMOKE amplitude can be further increased if losses in metal ribs are reduced. For a magnetoplasmonic grating with optimized geometry, we demonstrated the potential detection of biologically relevant analytes with sensitivity in the order of 10 2 nm/RIU (refractive index unit). Since the nanoarchitecture proposed is experimentally feasible with, e.g., nanolithography techniques, one may expect that the design strategy may inspire the development of efficient magnetoplasmonic sensing platforms.

Optimization of Magnetoplasmonic ε-Near-Zero Nanostructures Using a Genetic Algorithm

“…The corresponding sensitivity (absolute value of the slope) for this structure was found as (in excellent agreement with the GA optimization results). In addition, on the right vertical axis we show the corresponding figure of merit ( , where is the TMOKE line width for each n ), which, as noticed (in the order of ), is competitive with the current SPR approaches [ 36 ]. It is worth mentioning that we tried to optimize the structure with a Co-substrate for sensing.…”

Enhanced transverse magneto-optical Kerr effect using ferromagnetic metal perforated with nanopore arrays

“…6(c) presents the calculated FOM values by the black dots, which are significantly higher than the FOM values reported for magneto-optical structures. 22…”

“…Therefore, several nanostructure design strategies to improve the performance of T-MOKE devices have been proposed. In addition, the most efficient structure is the periodic nanoarchitecture comprising a nanostructured metallic grating on a ferromagnetic film 22,23 or the prism-based magnetoplasmonic structure. 24,25 However, miniaturization and ease of preparation of detection chips are now being considered owing to the development of detection technology, which requires the integration of detection chips into microfluidic devices.…”

Magnetoplasmonic Nanoantennas for On-Chip Reconfigurable Optical Wireless Communications

“…Inspiration came from the use of magnetic fields to control light propagation properties, which has been done since 1845 when Michael Faraday observed polarization rotation of linearly polarized light propagating parallel to an applied magnetic field. In the late 1870s, the Reverend John Kerr demonstrated the magneto-optical (MO) effects for linearly polarized light reflected from a magnetized surface. , These MO effects were essential for technological breakthroughs such as high-speed nonreciprocal optical isolators, − filters, data storage, (bio)­sensing, − and spectroscopy , devices. Many of these achievements have been made possible by integrating plasmonic effects, i.e., the resonant coupling of free density charge oscillations with the electric field component of light, with magneto-optical effects at the nanoscale.…”