J. Eur. Opt. Society-Rapid Publ. 2026, 22, 1 Ó The Author( s), published by EDP Sciences, 2026 https:// doi. org / 10.1051 / jeos / 2025050 Available online at: https:// jeos. edpsciences. org
Journal of the European Optical Society-Rapid Publications
RESEARCH ARTICLE
Experimental demonstration of optical energy transfer between the 0th and �1st orders diffracted by an all-dielectric resonant waveguide grating
Rosa Olloghe Mandoukou 1, Maxime Royon 1,*
, Arnaud Meyer 1, Maxime Darnon 1, Irvin Girault 1, Damien Jamon 1, William Ravisy 2, Gerges El Haber 2, Laurent Dubost 2, Samuel R. De Cotret 3, Oleh Fesiienko 3, Isabelle Verrier 1, and Yves Jourlin 1
1 |
Laboratoire Hubert Curien, UMR 5516, UJM, CNRS, IOGS, 18 rue du Professeur Benoit Lauras, 42000 Saint-Etienne, France |
2 |
HEF IREIS, ZI Sud – Avenue Benoit Fourneyron, 42160 Andrézieux-Bouthéon, France |
3 |
Institut Interdisciplinaire d’ Innovation Technologique( 3IT), Parc Innovation( P2-3000) 3000, Boulevard de l’ Université, Sherbrooke, Canada |
Received 4 November 2025 / Accepted 26 November 2025
Abstract. The energy transfer between the reflected 0th and �1st orders diffracted by a grating in the vicinity of the Littrow angle is experimentally demonstrated for the first time with an all-dielectric resonant waveguide grating under TE polarization. This effect has already been described in a theoretical approach but never proved by measurements. Contrary to classical configuration, the dielectric resonant diffractive structure is probed here from the grating backside to avoid signal disturbance. A transparent layer of very high refractive index( hydrogenated amorphous silicon: a-Si: H) is structured by e-beam lithography and plasma etching to create a resonant grating waveguide on a BK7 substrate. Agreement between modeling and experimental characterizations validates the energy transfer effect, opening the way to all-dielectric sensing devices.
Keywords: Resonant waveguide grating, Energy transfer, Hydrogenated amorphous silicon.
1 Introduction
In the past years, a large number of optical sensors based on plasmonic devices were described in the literature and have taken an important place for environmental or biological applications [ 1 – 3 ]. One means to couple light to plasmon waves and to achieve surface plasmon resonance is the use of metallic diffraction gratings under TM polarization [ 3, 4 ]. Generally, only the 0th reflected order is exploited to detect a change in the dielectric medium by the determination of the minimum in the angular or spectral signal [ 5 ]. However, to improve the device sensitivity, we previously demonstrated that the �1st reflected order diffracted by the grating can be useful when measured simultaneously with the 0th reflected order [ 6, 7 ]. The energy transfer between these two orders when tuning the wavelength or the incident angle, based on a lossless coupling of surface plasmonic modes, can be exploited as a highly sensitive sensor [ 8, 9 ]. Differential measurement of these two orders reduces the common mode noise and therefore improves sensitivity of the sensors based on this effect. Nevertheless, the device can only be probed from the grating top, meaning that the incident light and the reflected orders are
* Corresponding author: maxime. royon @ univ-st-etienne. fr perturbed by the medium to be tested, mainly when one considers liquid environment. To avoid this limitation, we propose here an all-dielectric structure that allows probing from the backside( substrate). The aim of this study is to demonstrate that, like for plasmonic sensors, it is possible to simultaneously use the 0th and �1st diffraction orders and that their energy transfer is possibly exploitable for a sensing system. To the best of our knowledge, this configuration represents the first realization of such an approach, opening new possibilities for advanced biosensor design.
In Section 2, the energy transfer is described briefly for the backside probing case and an explanation of the whole dielectric structure behavior is conducted. Section 3 is dedicated to the materials and methods to optimize the grating design and to fabricate the samples. Finally, Section 4 presents and discusses experimental results and is followed by a conclusion.
2 Optical energy transfer between the 0th and �1st grating orders
A diffraction grating is used in the present work to obtain, through an-all dielectric configuration, an optical energy
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