Kin Hung Fung

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We present an ultrabroadband thin-film infrared absorber made of sawtoothed anisotropic metamaterial. Absorptivity of higher than 95% at normal incidence is supported in a wide range of frequencies, where the full absorption width at half-maximum is about 86%. Such property is retained well at a very wide range of incident angles too. Light of shorter(More)
We demonstrate an efficient eigendecomposition method for analyzing the guided modes in metal nanoparticle chains. The proposed method has the advantage of simultaneously showing the dispersion relation and the mode quality. It can also separate the material properties from the geometrical properties. Its efficiency therefore does not depend on the(More)
Cathodoluminescence spectroscopy has been performed on silver nanoparticles in a scanning electron microscopy setup. Peaks appearing in the visible range for particles fabricated on silicon substrate are shown to arrive from excitation of out-of-plane eigenmodes by the electron beam. Monochromatic emission maps have been shown to resolve spatial field(More)
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. We study the electromagnetic response and surface electromagnetic modes in a(More)
Hexagonal boron nitride (hBN) is a natural hyperbolic material, which can also accommodate highly dispersive surface phonon-polariton modes. In this paper, we examine theoretically the mid-infrared optical properties of graphene-hBN heterostructures derived from their coupled plasmon-phonon modes. We find that the graphene plasmon couples differently with(More)
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. We show that the scattering interaction between a high energy electron and a(More)
We show in this work an oblique layered system that is capable of manipulating two dimensional subwavelength images. Through properly designed planar layered system, we demonstrate analytically that lateral image shift could be achieved with subwavelength resolution, due to the asymmetry of the dispersion curve of constant frequency. Further, image rotation(More)
We propose a vortex-like metamaterial device that is capable of transferring image along a spiral route without losing subwavelength information of the image. The super-resolution image can be guided and magnified at the same time with one single design. Our design may provide insights in manipulating super-resolution image in a more flexible manner.(More)
Two-dimensional optical materials, such as graphene, can be characterized by surface conductivity. So far, the transformation optics schemes have focused on three-dimensional properties such as permittivity ϵ and permeability μ. In this Letter, we use a scheme for transforming surface currents to highlight that the surface conductivity transforms in a way(More)
Light carries angular momentum, and as such it can exert torques on material objects. Applications of these opto-mechanical effects were limited initially due to their smallness in magnitude, but later becomes powerful and versatile after the invention of laser. Novel and practical approaches for harvesting light for particle rotation have since been(More)