Conventional optical components rely on the propagation through thick materials to control the amplitude, phase and polarization of light. Metasurfaces provide a new path for designing planar optical devices with new functionalities. In this approach, the control of the wavefront is achieved by tailoring the geometry of subwavelength-spaced nano antennas. By designing an array of low-loss dielectric resonators we create metasurfaces with an engineered wavelength-dependent phase shift that compensates for the dispersion of the phase accumulated by light during propagation. In this way the large chromatic effects typical of all flat optical components can be corrected. A flat lens without chromatic aberrations and a beam deflector are demonstrated. The suppression of chromatic aberrations in metasurface-based planar photonics will find applications in lightweight collimators for displays, and chromatically-corrected imaging systems.
Francesco Aieta is a researcher at HP Labs specializing in novel photonics devices for imaging and sensing applications. He worked as postdoctoral fellow at Harvard University and received a PhD in Applied Physics from the Politecnica delle Marche (Italy) in 2013. His present and past research are focused on the study of novel flat optical materials, design of devices from mid infrared to visible spectrum for biomedical applications as well as electronics consumer products. Other area of interest includes plasmonics, light matter interaction at the nanoscale, optical trapping in anisotropic environment and properties of liquid crystals. He is a member of the Optical Society of America.