Phys.org March 16, 2023 Metasurfaces have shown remarkable potential to manipulate many of light’s intrinsic properties, such as phase, amplitude, and polarization. An international team of researchers (Saudi Arabia, Macedonia, USA – New York University) has demonstrated a broadband multifunctional metasurface platform with the unprecedented ability to independently control the phase profile for two orthogonal polarization states of incident light over dual-wavelength spectra (ultraviolet to visible). They designed and fabricated multiple single-layered metasurfaces composed of bandgap-engineered silicon nitride nanoantennas and optically characterized to demonstrated broadband multifunctional light manipulation ability, including structured beam generation and meta-interferometer implementation. According to the researchers […]
Tag Archives: Metasurface
Meta-optics: The disruptive technology you didn’t see coming
Phys.org December 22, 2022 Optical metasurfaces interact strongly with light. The field has been driven by the key advantages of this concept, including the ultimate miniaturization of optical elements, empowering novel functionalities that process hidden modalities of light, and the opportunity to tune their properties on demand. Many applications with a focus on smart vision have emerged, foreseeing a meta-optical device under the hood of any robotic system. Nowadays the field is experiencing a solid industry pull that defines the challenges and research directions. In this review researchers in Australia have provided an overview of the applications of the field […]
Through the quantum looking glass
Science Daily September 12, 2022 Quantum state engineering mainly relies on spontaneous parametric downconversion and four-wave mixing, where one or two pump photons spontaneously decay into a photon pair. Both nonlinear effects require momentum conservation for the participating photons, which strongly limits the versatility of the resulting quantum states. Nonlinear metasurfaces have subwavelength thickness and allow the relaxation of this constraint; when combined with resonances, they greatly expand the possibilities of quantum state engineering. An international team of researchers (Germany, USA -Sandia National Laboratory) generated entangled photons via spontaneous parametric downconversion in semiconductor metasurfaces with high–quality factor, quasi-bound state in […]
A new strategy for active metasurface design provides a full 360-degree phase tunable metasurface
Phys.org May 2, 2022 Active metasurfaces have been proposed as one attractive means of achieving high-resolution spatiotemporal control of optical wavefronts, having applications such as LIDAR and dynamic holography. An international team of researchers (South Korea, USA – University of Wisconsin) has developed an electrically tunable metasurface design strategy that operates near the avoided crossing of two resonances, one a spectrally narrow, over-coupled resonance and the other with a high resonance frequency tunability. It displayed an upper limit of 4π range of dynamic phase modulation with no significant variations in optical amplitude, by enhancing the phase tunability through utilizing two […]
New metalens focuses light with ultra-deep holes
Nanowerk October 13, 2021 Most metasurfaces use monolith-like nanopillars to focus, shape and control light. The taller the nanopillar more versatile control of each color of light. But very tall pillars tend to fall or cling together. Researchers at Harvard University developed a metasurface with more than 12 million needle-like holes drilled into a 5-micrometer silicon membrane rather than very tall pillars to focus light to a single spot. The diameter of these long, thin holes is only a few hundred nanometers, making the aspect ratio nearly 30:1. The hole size variation bends the light towards the lens focus. Holes […]
Harnessing the dark side
Nanowerk July 13, 2021 Optical singularities, which appear completely dark, typically occur when the phase of light with a specific wavelength, or color, is undefined. Researchers at Harvard University have developed a new way to control and shape optical singularities. The metasurface tilts the wavefront of light in a very precise manner over a surface so that the interference pattern of the transmitted light produces extended regions of darkness. Their approach allows precise engineering of dark regions with remarkably high contrast. Engineered singularities could be used to trap atoms in dark regions and improve super high-resolution imaging. As darkness has […]
New type of metasurface allows unprecedented laser control
Phys.org June 29, 2021 An international team of researchers (USA – Harvard University, Italy) has developed a tunable laser that has two components—a laser diode and a reflective metasurface. The metasurface surface uses supercells, groups of pillars which work together to control different aspects of light. It is designed so that only the selected wavelength has the correct direction to enter back in the diode enabling the laser to operate only at that specific wavelength. The wavelength can be changed by moving the metasurface with respect to the laser diode. The shape of the laser beam can be fully controlled […]