We present a comprehensive investigation of resonant all-dielectric multi-layers. We first introduce a numerical as well as analytical optimization based on admittance recurrence law. We then address the technological aspects of the fabrication using dual-ion-beam sputter deposition. Using the optimally fabricated structures, we carry out experiments to optically characterize their responses in the near and far fields. Previously, our optimization strategy had been based on maximizing the absorption within the dielectric stack  for any illumination conditions without altering the field enhancement. Recently, we have improved this process by introducing a single zero-admittance layer that allows defining the field enhancement localization within the multi-layer . Similarly to the Kretschmann configuration for surface plasmon resonances (SPR), these resonant all-dielectric components work under total internal reflection but they can support field enhancements up to 104-105. From a theoretical point of view, the enhancement is not intrinsically limited (except for nonlinear phenomena or material damages under high flux), and it is therefore the illumination bandwidths (angular divergence and spectral range), which mainly limit the resulting field enhancement . We will introduce the resonant all-dielectric components, demonstrate their potential for sensing applications and give a brief comparison with SPR .
The authors acknowledge the PSA group for financial support of this work, the ANRT for their support through the CIFRE program and the RCMO Group of the Institut Fresnel for the realization of the coatings. This work is part of the OpenLab PSA/AMU: Automotive Motion Lab through the StelLab network.
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Multi-dielectric thin films are usually studied as waveguiding structures with low absorption effect
because of the low imaginary part of the refractive index. However, when properly designed, we
demonstrated that multi-dielectric stacks can sustain large optical fields. We briefly present here
our design method leading the fabrication of such multi-dielectric stacks, which can be optimized
for arbitrary wavelengths, indices or polarizations. We then report on our experimental character-ization in near and far field, using a photon scanning tunneling microscope and scattering optical
setup, respectively. This investigation may find applications for ultra-sensitive optical sensors or
integrated light sources to mention a few.
Currently, the utilization of high power ultrafast lasers to induce optical changes in structures for the purpose of locally
drawing patterns with dimensions inferior to the diffraction limit is well-established and controlled. Using this technique,
we aim to modify the refractive index and/or the geometrical parameters of an optical interferential filter composed of
successive thin layers. This local optimization will then allow the improvement or tuning of the performances of the
optical filters. Thereafter, it is necessary to characterize these local modifications to achieve the final response of the
expected filter. In our work, we developed a dedicated optical system, based on Fabry-Perot interferometry, to measure
optical thickness, ranging from 10-3 to 10-4, with a high spatial resolution (in the order of 5×5μm). We present here our
preliminary results carried out on calibrated test samples.
Conference Committee Involvement (2)
Active Photonic Platforms XII
23 August 2020 | San Diego, California, United States
Active Photonic Platforms XI
11 August 2019 | San Diego, California, United States