Towards dynamic polarization control with optical metasurfaces (Conference Presentation)

Optical polarization is an important characteristic of electromagnetic waves that has a significant impact on number of applications, such as information delivery, 3D imaging, and quantum computation. Metasurfaces, sort of artificially designed planar structure, have attracted immense attention due to their ability to control the amplitude and phase of electromagnetic waves at a subwavelength scale. Metasurfaces hold promise for the fields of nonlinear dynamics, light beam shaping, quantum computation, etc. Beside these promising applications, metasurfaces can also be used for versatile polarization generation in a compact device dimension. Therefore, metasurfaces can be used for creation of flat optical devices with novel functionalities. In this talk, I will discuss how we can generate versatile polarization states by using metasurfaces. Firstly, I will describe geometric phase metasurfaces, which can be used for passive polarization control. We demonstrate six metasurface chips integrated on a single sample, in which each chip is responsible for generating one specific polarization state thus generating versatile polarization sates. Subsequently, I will discuss a scheme of active polarization modulation by using indium tin oxide (ITO)-based tunable metasurfaces. By suitably biasing the metasurface, the linearly-polarized incident light can be actively converted to a cross-polarized, circularly-polarized or elliptically-polarized light