Dielectric nanoantennas: from passive to active functionalities (Conference Presentation)

Dielectric nanoantennas and metasurfaces have recently become a new trend in nanophotonics thanks to their low-loss resonant behaviour based on both electric and magnetic resonant modes [1]. Most of the recent developments in this field are related to silicon nanostructures, which demonstrate excellent resonances in the visible and near-IR parts of the spectrum. Other material platforms such as titanium dioxide (TiO2), gallium nitride (GaN), gallium arsenide (GaAs) and gallium phosphide (GaP) have also been explored to generate low-loss resonances at visible frequencies and explore linear and nonlinear optical effects. Though some of these materials (e.g. GaAs, GaN and GaP) are well-known active semiconductors famous for their emission properties, so far, only passive nanoantenna-based device functionalities have been realized. In this presentation, I will first review the recent progress of our team in the field of dielectric nanoantennas and metasurfaces demonstrating some unique passive device functionalities related to high-angle light bending and focusing. Then I will discuss active light-emitting devices based on the nanoantenna concepts. In particular, I will demonstrate the first optically-pumped laser based on semiconductor nanoantenna structures. Finally I will present active tuning of nanoantenna characteristics using external electrical signals. References: 1) A. I. Kuznetsov et al., “Optically resonant dielectric nanostructures”, Science 354, aag2472 (2016).