Research Article

Experimental demonstration of optical energy transfer between the 0th and −1st orders diffracted by an all-dielectric resonant waveguide grating

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

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

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.