Compound nonlinear metasurfaces for advanced light manipulation

Introduction

Metasurfaces have garnered significant attention in both scientific and industrial domains due to their capabilities in wavefront manipulation, facilitated by arrays of subwavelength artificial structures. Substantial advancements in nonlinear optics at the nanoscale can be realized through the use of high-refractive-index material metasurfaces, which incorporate low-loss dielectric nanoparticles that support nontrivial resonant optical modes within the subwavelength regime. The coupling between adjacent nanoparticles enables metasurfaces to support narrow-band collective resonances, associated with the excitation of quasi-trapped modes that exhibit significantly higher Q-factors compared to individual nanoresonators, and provides a versatile and powerful platform for controlling and enhancing nonlinear optical processes at the nanoscale. By leveraging the nonlinear optical properties of meta-atoms, nonlinear metasurfaces present a wide array of possibilities, leading to the development of efficient next-generation flat-optics devices that match the capabilities of conventional bulk components. Driven by mode-matching, resonances, and relaxed phase-matching conditions, all-dielectric resonant compound metasurfaces are emerging as versatile tools for ultrasensitive detection of molecular fingerprints, nonlinear image generation, frequency conversion, quantum light sources, and the broadening of the spectral range accessible with existing lasers.

Topic

The main objective of this project is to explore the properties of compound metasurfaces and to develop a new model and techniques for engineering of multi-layered dielectric metasurfaces.  The implementation of multilayered structures, consisting of two or more independent metasurfaces functioning as sequential optical elements, offers significantly enhanced control over the amplitude, phase, and polarization state of light. This is achieved through a flat, nanostructured surface while maintaining a monolithic and compact design. Furthermore, multilayered metasurfaces enable the tuning of metasurface resonances to improve light manipulation. Despite the increased complexity in fabricating these multilayered nanostructures, this approach is considered viable in the field of nonlinear metaoptics. It extends the interaction length of the fundamental pump with the material, thereby enhancing nonlinear generation and providing an additional degree of freedom for controlling nonlinear processes. The scientific objective of this project is to develop all-dielectric resonant compound metasurfaces for specific devices, considering fabrication technologies compatible with industrial applications.

This PhD project combines optical design and device characterization.

The candidate

You are a highly motivated student, with background in nano-engineering, physics, material science, electrical engineering, or related. You have an interest in nanofabrication and flat optics applications, both from design and characterization side. It is expected that you will present results regularly. You are a team player and have good communication skills as you will work in a multidisciplinary and multicultural team spanning several imec departments. Given the international character of imec, an excellent knowledge of English is a must.