Work

Optical spatial differentiation with suspended subwavelength gratings

Year: 2021

Type: article

Abstract: We investigate first- and second-order spatial differentiation of an optical beam transverse profile using guided-mode resonances in thin, suspended subwavelength gratings. Highly reflective one-dimensional gratings are patterned on freestanding 200 nm-thick silicon nitride membranes using Electron Beam Lithography and plasma etching. The optical transmission of these gratings, designed for illumination with either TM or TE polarized light, are experimentally measured under normal and oblique incidence and found to be in excellent agreement with the predictions of an analytical coupled-mode model as well as Rigorous Coupled Wave Analysis numerical simulations. Intensity profiles consistent with high quality first- and second-order spatial differentiation of a Gaussian beam are observed in transmission at oblique and normal incidence, respectively. Such easy-to-fabricate, ultrathin and loss-free optical components may be attractive for beam shaping and optical information processing and computing.

Source: Optics Express

DOI: 10.1364/oe.416801

Authors: Alexios Parthenopoulos, Ali Akbar Darki, Bjarke R. Jeppesen, Aurélien Dantan

Institution: Aarhus University

Language: English

Topic: Optical Coatings and Gratings

Subfield: Surfaces, Coatings and Films

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,270

Funder: Danmarks Frie Forskningsfond