Manipulating light at the nanoscale
Antenna resonators are at the heart of modern radio and microwave frequency communications technologies. Antenna concepts have been recently extended to the infrared and optical frequency domains, greatly enhancing light-matter interactions in a variety of nanophotonic systems and eventually launching the field of metasurfaces ─ the optical frequency analogs of phased array radar. This ability to manipulate light at subwavelength scales have led to numerous demonstrations of flat optical elements including, lenses, beam deflectors , holograms, light sources etc. Thus far, metals have played a pivotal role in this field, due to their ability to support surface plasmon oscillations. However, metals suffer from high ohmic losses in the visible to infrared spectral ranges and are incompatible with CMOS fabrication. Growing interest has recently shifted to high-index dielectric and semiconductors as means to overcome metallic losses while facilitating light manipulation at subwavelength scales. In this talk, I discuss the rich optical response of dielectric antenna resonators arising from multipolar Mie resonances. I demonstrate bottom-up techniques for fabricating nanoparticles and metasurfaces with controlled size and shape and the ability to engineer their response across the visible to mid-infrared spectral ranges. I show how the wealth of electric and magnetic resonances in these nanostructures can be exploited to manipulate both classical and quantum properties of light. I also present various materials and approaches for dynamic control of light such as phase-change materials, semiconductors and 2D materials.