The phase of an optical system being a circularly variable becomes undefined when the intensity vanishes, which is generally referred to as optical singularity. At the intensity vanishing point, singular phase or topological phase appears. In fact, optical singularity is pervasive in many physical phenomena such as vortex beams, reflection at Brewster’s angle, and perfect absorption and so on. Associated with the singularity point, the optical systems exhibit many nontrivial behaviors which could underpin tremendous nanophotonic applications. In this talk, I will present the utilization of such singular optics for metasurfaces as well as for far-field superresolution imaging. In the first part, we show that the losses of atomic thin layered materials can be used to create points of darkness (zero reflection). The singular phase behavior of the optical systems crossing the darkness point can lead to an abrupt phase jump of pi. Harnessing the Heaviside phase jump, we demonstrate atomic thin metasurface for light field manipulations. In the second part, we show that high-index dielectric nanostructures can support radiationless anapole state allowing vanishing far-field scattering accompanying with strong near fields. The unique feature can be utilized for giant photothermal nonlinear scattering modulations as well as application in far-field superresolution localization microscopy with an accuracy up to 40 nm.
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