Work

Sequentially PARMS-coated sub-nanometric film stacks for UV applications

Year: 2025

Type: article

Abstract: We present a comparative study of two types of materials with tunable artificial refractive indices that were obtained by sequentially coating sub-nanometric film stacks of Ta2O5/SiO2 and Nb2O5/SiO2. These sub-nanometric film stacks were fabricated using Plasma-Assisted Reactive Magnetron Sputtering and simultaneous co-sputtering of two targets. The thickness of individual sub-layers was controlled by the turntable rotation speed, and the ratio between the two materials was determined by the power applied to the respective targets. We show that these materials with tunable refractive indices present an interesting alternative to classical high-refractive-index materials for UV applications. However, the achievable bandgap is not as large as classical materials like HfO2, and the lower the bandgap of the high-refractive-index material, the lower the bandgap of the nanolaminate at a given refractive index.

Source: Optics Letters

DOI: 10.1364/ol.565979

Authors: Julien Lumeau, Fabien Lemarchand, Supratik Dasgupta

Institutions: Institut Fresnel, Centrale Méditerranée

Language: English

Topic: Optical Coatings and Gratings

Subfield: Surfaces, Coatings and Films

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funder: Centre National d’Etudes Spatiales

Award: G5130114174