Metasurfaces are ultrathin planar nanostructure made of subwavelength metallic or dielectric elements which can be designed to efficiently control the light characteristics such as polarisation, dispersion, amplitude, and phase. The efficient 2π-phase control capability with high transmittance feature makes the metasurfaces versatile tools for the wavefront manipulation. The performance of the metadevices can be significantly enhanced by utilizing the phase discretization efficiently in designing metadevices. Furthermore, due to subwavelength wave discretization, new functionalities can be achieved by governing the phase response.

In this seminar, first, I will demonstrate the efficiently control of deflection angle with high diffraction efficiency in the visible wavelength. I will also discuss deeply subwavelength metasurface resonators for terahertz wavefront manipulation. Then, I will focus on a novel dielectric resonant metagrating-based highly sensitive optical biosensing technique. Finally, I will demonstrate Mieresonant dielectric metasurfaces can be used as a passive filter to perform the image processing in a form of edge detection of a target object.