How metasurfaces work?
How metasurfaces work?
The principle of operation of metasurfaces is based on the phenomenon of diffraction. Any flat periodic array can be viewed as a diffraction lattice, which splits the incident light into a few rays.
What is optical metasurfaces?
Optical metasurfaces, as a two-dimensional counterpart of metamaterials, have garnered much attention in the scientific community due to the versatile capabilities to manipulate electromagnetic (EM) waves within an ultrathin surface (Chen et al., 2016; Genevet et al., 2017; Luo, 2019; Monticone and Alù, 2017; Neshev …
What is a metasurface used for?
Metasurface optical holography It has been used to design planar optical functional elements such as ultrathin metasurface lens, metasurface waveplates, polarization beam splitter and so on. More generally, metasurface is capable of shaping the general and complex wavefront of light through holography techniques.
What is Metasurface lens?
Metasurfaces, the corresponding two-dimensional metamaterials, can flexibly control the amplitude, phase, and polarization of light through sub-wavelength units, compared with the traditional lens that relies on the modulated light beam to accumulates the phase delay during the transmission, it is smaller in size.
What are metamaterials and Metasurfaces?
Metamaterials are artificially engineered materials with interesting optical properties, including a negative refractive index, cloaking and Doppler effect. Specifically, two-dimensional metamaterials, i.e., metasurfaces, have unique interface transmission and reflection properties resulting from surface impedance.
What is electromagnetic cloaking?
What is an electromagnetic cloak? This is a device which makes an object “invisible” for electromagnetic radiation in a certain frequency range. Of course, the most exciting applications can be envisaged for cloaks working in the visible part of the spectrum.
What are metamaterials made of?
Metamaterials are composite materials typically composed of arrays of small metallic resonators structured on the microscale or nanoscale (McPhedran, Shadrivov, Kuhlmey, & Kivshar, 2011; Walser, 2003).
What is a meta atom?
In metamaterials the cell acts as a meta-atom, a larger scale magnetic dipole, analogous to the picometer-sized atom. For meta-atoms constructed from gold, μ < 0 can be achieved at telecommunication frequencies but not at visible frequencies.
What is subwavelength scale?
Sub-wavelength optics is the study of light on a spatial scale smaller than its wavelength. Conventionally, the minimum length scale on which a beam of light can operate is equal to half its wavelength. However, by coupling light to matter, photonic effects can be realised on a much smaller spatial scale.
How are metamaterials used?
Metamaterials are composite media that can be engineered to exhibit unique electromagnetic properties. Made up from subwavelength building blocks (most often based on metals), these metamaterials allow for extreme control over optical fields, enabling effects such as negative refraction to be realized.
How are metasurfaces used in the real world?
Metasurfaces enable a spatially varying optical response, mold optical wavefronts into shapes that can be designed at will, and facilitate the integration of functional materials to accomplish active control and greatly enhanced nonlinear response.
How are metasurfaces improving the control of light?
In the past few years, metasurfaces have achieved groundbreaking progress, providing unparalleled control of light, including constructing arbitrary wave fronts and realizing active and nonlinear optical effects. This article provides a systematic review of the current progress in and applications of optical metasurfaces,…
What are the characteristics of an acoustic metasurface?
Acoustic metasurfaces derive their characteristics from the interaction between acoustic waves and specifically designed materials. The field is driven by the desire to control acoustic wave propagation using compact devices and is governed by fundamental and physical principles that provide the design rules and the functionality of a wave.
Why are ultrathin metasurfaces better for optical devices?
The 2D nature of ultrathin metasurfaces also allows for more compact optical devices and reduced optical losses compared with their bulk counterparts. Moreover, the deflection of light on a metasurface does not depend on propagation effects as strongly as in 3D metamaterials, which reduces the effect of dispersion.
