Cross-shaped resonators for BICs in mid-IR fabricated using multiphoton lithography

Artificially designed materials, known as metamaterials, have changed the way we understand nature and create a new perspective to the optical, and not only, world and overcome almost any limitations of natural materials. Fabrication of 3D optical metamaterials, which would enable the use of their full potential, remains challenging due to the limitations of conventional manufacturing techniques. Multiphoton lithography (MPL) is a true 3D printing process relying on direct laser writing (DLW) that enables the capability of structuring subwavelength features. In this work, we present the development of three different cross-shaped resonator’s designs and subsequently their fabrication using MPL, to enhance bound states in the continuum (BICs) in mid-IR frequencies.