Phys.org October 16, 2024 Nonlinear metasurfaces are used for infrared imaging and spectroscopy. However, due to their low conversion efficiencies several strategies have been adopted to enhance their performances. Using resonances at signal or nonlinear emission wavelengths results in a narrow operational band of the nonlinear metasurfaces, which has bottlenecked many applications, including nonlinear holography, image encoding, and nonlinear metalenses. An international team of researchers (UK, Australia) introduced a new nonlinear imaging platform to overcome this issue. They demonstrated broadband nonlinear imaging for arbitrary objects using metasurfaces. A silicon disk-on-slab metasurface was introduced with an excitable guided-mode resonance at the […]
Tag Archives: Metasurfaces
Researchers unveil single-shot and complete polarization imaging system using metasurfaces
Phys.org May 2, 2024 When light scatters off an object, its polarization, in general, changes—a transformation described by the object’s Mueller matrix. Mueller matrix imaging is an important technique in science and technology to image the spatially varying polarization response of an object of interest, to reveal rich information otherwise invisible to traditional imaging. An international team of researchers (USA – UC San Diego, Germany) conceptualized, implemented, and demonstrated a compact Mueller matrix imaging system—composed of a metasurface to produce structured polarization illumination and a metasurface for polarization analysis—that could, in a single shot, acquire all 16 components of an […]
Micro-optical technology based on metamaterials takes center stage
Phys.org August 30, 2023 To date research on metasurfaces has mainly focused on the full control of electromagnetic characteristics, including polarization, phase, amplitude, and even frequencies. Consequently, versatile possibilities of electromagnetic wave control have been achieved, yielding practical optical components such as metalenses, beam-steerers, metaholograms, and sensors. Researchers in South Korea focused on integrating the metasurfaces with other standard optical components for commercialization with miniaturization trends of optical devices. In this review they described and classified metasurface-integrated optical components, and subsequently discussed their promising applications with metasurface-integrated optical platforms including those of augmented/virtual reality, light detection and ranging, and sensors. […]
Source-shifting metastructures composed of only one resin for location camouflaging
Science Daily May 30, 2023 Researchers in Japan numerically demonstrated an inverse design of a structure for camouflaging the location of a sound source as if the sound emanated from a different location. They used a topology optimization approach used in acoustic elastic coupled problems, the difference between the sound pressure fields emanating from an actual source and a virtual source, was the objective function infimized in camouflaging the sound source. Optimal topologies of elastic structures made of acrylonitrile butadiene styrene were designed for the camouflaging purpose, acoustic metamaterials were not used. The metastructures (source-shifters) were expressed at the design […]
Leaky-wave metasurfaces: A perfect interface between free-space and integrated optical systems
Phys.org May 8, 2023 Metasurfaces have been rapidly advancing our command over the many degrees of freedom of light; however, so far, they have been mostly limited to manipulating light in free space. Metasurfaces integrated on top of guided-wave photonic systems have been explored to control the scattering of light off-chip with enhanced functionalities. However, these efforts have so far been limited to controlling one or two optical degrees of freedom at best. A team of researchers in the US (Columbia University, City University of New York) has developed leaky-wave metasurfaces, which are based on symmetry-broken photonic crystal slabs that […]
Towards a new antenna paradigm with waveform-selective metasurfaces
Nanowerk February 28, 2023 Although various modulation schemes have been proposed to efficiently use the limited frequency resources by exploiting several degrees of freedom, antenna performance is essentially governed by frequency only. An international team of researchers (Japan, Italy, USA – UK) has proposed an antenna design concept based on metasurfaces to manipulate antenna performances in response to the time width of electromagnetic pulses. They numerically and experimentally showed that by using a proper set of spatially arranged metasurfaces loaded with lumped circuits, ordinary omnidirectional antennas could be reconfigured by the incident pulse width to exhibit directional characteristics varying over […]
Nanoparticles control flow of light like road signs direct traffic
Science Daily June 20, 2022 An class of metasurface functionalities is associated with asymmetry in both the generation and transmission of light with respect to reversals of the positions of emitters and receivers. The nonlinear light–matter interaction in metasurfaces offers a promising pathway towards miniaturization of the asymmetric control of light. An international team of researchers (Germany, Australia, Singapore) has demonstrated asymmetric parametric generation of light in nonlinear metasurfaces by assembling dissimilar nonlinear dielectric resonators into translucent metasurfaces that produce images in the visible spectral range on being illuminated by infrared radiation. By design, the metasurfaces produce different and completely […]
Researchers combine piezoelectric thin film and metasurfaces to create lens with tunable focus
EurekAlert February 17, 2022 Using metasurfaces researchers in Norway designed a device in which a metasurface is suspended on a membrane ring made of a thin-film lead zirconate titanate (PZT) film, which allows the PZT to move the metasurface when a voltage is applied. To demonstrate how MEMS-metasurfaces could function as a varifocal lens doublet, they placed a second metasurface lens after the MEMS-metasurface. Varying the separation distance between the lenses through MEMS displacement allowed researchers to tune the focal point of the lens doublet on the fly. The researchers showed that applying 23 volts allowed the PZT membrane to […]