Strong modification of the magnetic local density of optical state through magnetic nanoantennas

International audienceWe theoretically describe how one can achieve unprecedented enhancement of both the total and radiative decay rate of a magnetic dipole moment by using resonating nanoantennas designed to strongly enhance the optical magnetic fiel

Strong modification of the magnetic local density of optical state through magnetic nanoantennas

International audienceWe theoretically describe how one can achieve unprecedented enhancement of both the total and radiative decay rate of a magnetic dipole moment by using resonating nanoantennas designed to strongly enhance the optical magnetic fiel

Strong Modification of Magnetic Dipole Emission through Diabolo Nanoantennas

International audienceMagnetic dipole transitions in matter are known to be orders of magnitude weaker than their electric dipole counterparts. Nanophotonic and plasmonic structures have the potential of strongly enhancing the optical magnetic fields in the near field, making these nanostructures ideal candidates to control and enhance the emission of magnetic dipole transitions. Here we theoretically investigate the potential of resonant optical nanoantennas based on diabolo and on metal–insulator–metal diabolo configurations to strongly modify the magnetic dipole of emitters. We find that both configurations provide unprecedented 102- to 103-fold enhancement of the total and the radiative decay rates of a magnetic dipole moment. We show that these two nanoantennas have opposed effects on the quantum yield of the magnetic dipole, translating into different antenna efficiencies. Furthermore, by using a magnetic dipole moment as a theoretical optical nanosensor, we numerically mapped the behavior of the magnetic local density of states (MLDOS) in the entire plane close to the diabolo nanoantenna. We demonstrate the strong confinement and local enhancement of the MLDOS by the nanoantenna. As such, these results underscore the unique ability of optical nanoantennas to control light emission from magnetic dipoles, opening new technological avenues in the magneto-optical domain

Full vectorial imaging of electromagnetic light at subwavelength scale

International audienceWe propose a concept of near-field imaging for the complete experimental description of the structure of light in three dimensions around nanodevices. It is based on a near-field microscope able to simultaneously map the distributions of two orthogonal electric-field components at the sample surface. From a single 2D acquisition of these two components, the complementary electric and magnetic field lines and Poynting vector distributions are reconstructed in a volume beneath the sample using rigorous numerical methods. The experimental analysis of localized electric and magnetic optical effects as well as energy flows at the subwavelength scale becomes possible. This work paves the way toward the development of a complete electromagnetic diagnostic of nano-optical devices and metamaterials

Plasmonic nanoantennas for enhanced single molecule analysis at micromolar conentrations

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Matching Nanoantenna Field Confinement to FRET Distances Enhances Forster Energy Transfer Rates

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