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 […]
Tag Archives: Free-space communication
High-speed, efficient, and compact electro-optic modulators for free space
Science Daily June 7, 2022 Modulators based on metasurface architectures that modulate free-space light at gigahertz (GHz) speeds can boost flat optics technology by microwave electronics for active optics, diffractive computing, or optoelectronic control. An international team of researchers (USA – Harvard University, University of Washington, Switzerland) has demonstrated a modulator that consists of a thin layer of an organic electro-optic material deposited on top of a metasurface etched with sub-wavelength resonators integrated with microwave electronics. When a microwave field is applied to the electro-optical material, its refractive index changes, changing the intensity of light that is being transmitted by […]
Researchers propose the use of quantum cascade lasers to achieve private free-space communications
Phys.org June 22, 2021 An international team of researchers (France, Germany, USA – UCLA, University of New-Mexico) shows that two uni-directionally coupled quantum cascade lasers operating in the chaotic regime and the synchronization between them allow for the extraction of the information that has been camouflaged in the chaotic emission. This building block represents a key tool to implement a high degree of privacy directly on the physical layer. The team has built a proof-of-concept communication at a wavelength of 5.7 μm with a message encryption at a bit rate of 0.5 Mbit/s. Their demonstration of private free-space communication between […]