Phys.org January 17, 2023 Optically active defects in 2D materials, such as hexagonal boron nitride (hBN) and transition-metal dichalcogenides (TMDs), are an attractive class of single-photon emitters. An international team of researchers (USA – UC Santa Barbara, Japan) has demonstrated a novel approach to precisely align and embed hBN and TMDs within background-free silicon nitride microring resonators. Through the Purcell effect, high-purity hBN emitters exhibited a cavity-enhanced spectral coupling efficiency of up to 46% at room temperature, exceeding the theoretical limit (up to 40%) for cavity-free waveguide-emitter coupling and demonstrated nearly a 1 order of magnitude improvement over previous work. […]
Tag Archives: Photonic chips
Photonics – extending the spectrum
Nanowerk December 6, 2022 Despite remarkable manufacturing advantages, reliance on silicon-based waveguides currently limits the spectral window available to photonic integrated circuits (PICs). A team of researchers in the US (industry, UC Santa Barbara, Caltech) has developed a technique to enable photonic chips to operate in the visible-to-near-infrared spectrum by directly uniting III–V materials with silicon nitride waveguides on Si wafers. Using this technology, they fabricated a fully integrated PIC at photon energies greater than the bandgap of silicon, demonstrating essential photonic building blocks, including lasers, amplifiers, photodetectors, modulators, and passives, all operating at submicrometre wavelengths. Using this platform, they […]
Unexpected light behavior may be harnessed to improve optical communications and sensors
Phys.org April 21, 2022 Waves entering a spatially uniform lossy medium typically undergo exponential intensity decay, arising from either the energy loss or the evanescent penetration during reflection. A team of researchers in the US (NIST, University of Maryland, Texas Tech University, Carnegie Mellon University) proposed and demonstrated exponential decay free wave propagation in a purely lossy medium. They observed up to 400-wave deep polynomial wave propagation accompanied by a uniformly distributed energy loss across a nanostructured photonic slab waveguide with exceptional points. Using coupled-mode theory and fully vectorial electromagnetic simulations they predicted deep wave penetration manifesting spatially constant radiation […]
Silicon waveguides move us closer to faster, light-based logic circuits
Phys.org February 8, 2021 Wiring up the transistors of an optical circuit with silicon waveguides is an important requirement to make compact, highly integrated chips. However, silicon is a strong absorber of visible light. To circumvent the absorption issue researchers in Switzerland used high contrast grating consisting of nanometer sized “posts” lined up in such a way that light passing through the posts interferes destructively with light passing between posts making sure that no light can “leak” through the grating. Most of the light gets reflected inside the waveguide. They showed that there was a loss of only 13 percent […]
‘Valleytronics’ discovery could extend limits of Moore’s Law
Science Daily May 1, 2018 An international team of researchers (USA – UC Berkeley, Lawrence Berkeley National Laboratory, Singapore, China) has shown that tin(II) sulfide is able to absorb different polarizations of light and then selectively reemit light of different colors at different polarizations. This is useful for concurrently accessing both the usual electronic and the material’s degrees of freedom. SnS possesses selectivity at room temperature without additional biases apart from the excitation light source. With this finding, researchers will be able to develop operational valleytronic devices, which may one day be integrated into electronic circuits. The unique coupling between […]