Phys.org January 19, 2023 Achieving hopfions with light waves is very elusive. An international team of researchers (UK, China) proposed and demonstrated photonic counterparts of hopfions with exact characteristics of Hopf vibration, Hopf index, and Hopf mapping from real-space vector beams to homotopic hyperspheres representing polarization states. They experimentally generated photonic hopfions with on-demand high-order Hopf indices and independently controlled topological textures, including Néel-, Bloch-, and antiskyrmionic types. They also demonstrated a robust free-space transport of photonic hopfions, thus showing the potential of hopfions for developing optical topological informatics and communications. According to the researchers their work provides a theoretical […]
Category Archives: Photonics
Photonic chip with record-breaking radio frequency dynamic range
Phys.org December 22, 2022 An international team of researchers (the Netherlands, China, Switzerland) has developed a multi-functional photonic integrated circuit that enables programmable filtering functions with record-high performance using versatile complex spectrum tailoring enabled by an all-integrated modulation transformer and a double injection ring resonator as a multi-function optical filtering component. They demonstrated reconfigurable filter functions with record-low noise figure and a RF notch filter with ultra-high dynamic range. According to the researchers their work breaks the conventional and fragmented approach of integration, functionality and performance that currently prevents the adoption of integrated microwave photonic systems in real applications…read more. […]
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 […]
New device can control light at unprecedented speeds
Nanowerk November 29, 2022 Harnessing the full complexity of optical fields requires the complete control of all degrees of freedom within a region of space and time. An international team of researchers (USA – MIT, industry, State University of New York, Rochester Institute of Technology, ARL (Rome), UK, Canada) resolved this challenge with a programmable photonic crystal cavity array enabled by four key advances: (1) near-unity vertical coupling to high-finesse microcavities through inverse design; (2) scalable fabrication by optimized 300 mm full-wafer processing; (3) picometre-precision resonance alignment using automated, closed-loop ‘holographic trimming’; and (4) out-of-plane cavity control via a high-speed μLED […]
Researchers develop laser that could ‘reshape the landscape of integrated photonics’
Phys.org October 24, 2022 A team of researchers in the US (University of Rochester, UC Santa Barbara, Caltech, Clemson University) has developed multi-color integrated laser that emits high-coherence light at telecommunication wavelengths allows laser-frequency tuning at record speeds and can be configured at the visible band. Using a hybrid integrated III-V/Lithium Niobate structure they demonstrated several essential capabilities that have not existed in previous integrated lasers. These include a record-high frequency modulation speed of 2 exahertz/s and fast switching at 50 MHz, both of which are made possible by integration of the electro-optic effect. The device co-lases at infrared and […]
Allying meta-structures with diverse optical waveguides for integrated photonics and more
Phys.org December 27, 2021 An international team of researchers (China, USA – Pennsylvania State University, Stanford University, Italy) reviewed recent advances in meta-structured waveguides that synergize various functional subwavelength photonic architectures with diverse waveguide platforms, such as dielectric or plasmonic waveguides and optical fibers, summarized foundational results and representative applications, cataloged brief physical models with explicit design tutorials, and highlighted how meta-optics can infuse new degrees of freedom to waveguide-based devices and systems. They discussed current challenges and outlined emerging opportunities of the field for applications in photonic integrated circuits, biomedical sensing, and artificial intelligence…read more. Open Access TECHNICAL ARTICLE
Shifting colors for on-chip photonics
Nanowerk November 24, 2021 Today, most frequency shifters are either too inefficient, losing a lot of light in the conversion process, or they can’t convert light in the gigahertz range. A team of researchers in the US (Harvard University, Caltech, industry) etched coupled ring-resonators and waveguides on thin-film lithium niobate. In the first device, two coupled resonators form a figure eight-like structure. Input light travels from the waveguide entering as one color and emerging as another. It provides frequency shifts as high as 28 gigahertz with about 90% efficiency. It can be reconfigured as tunable frequency-domain beam splitters. The second device […]
Photon-phonon breakthrough
Science Daily October 8, 2021 By combining the strong coupling between topological photons with phonons in hexagonal boron nitride (hBN), researchers at the City College of New York demonstrated a platform to control and guide hybrid states of light and lattice vibrations. The observed topological edge states of phonon-polaritons are found to carry nonzero angular momentum locked to their propagation direction, which enables their robust transport. Thus, these topological quasiparticles enable the funneling of infrared phonons mediated by helical infrared photons along arbitrary pathways and across sharp bends. This opens opportunities for applications ranging from Raman and vibrational spectroscopy with […]
Researchers create entangled photons 100 times more efficiently than previously possible
Phys.org December 17, 2020 Current methods of creating entanglement are inefficient, requiring a torrent of incoming laser light comprising hundreds of millions of photons before a single entangled photon pair will grudgingly drip out at the other end. Based on their earlier research, researchers at the Stevens Institute of Technology carved extremely high-quality racetrack-shaped microcavities into flakes of lithium niobate crystal. The cavities internally reflect photons with very little loss of energy, enabling light to circulate longer and interact with greater efficiency. By fine-tuning additional factors such as temperature, the team was able to create an unprecedentedly bright source of […]
Research develops new theoretical approach to manipulate light
EurekAlert December 8, 2020 Researchers in the UK re-examined the refractive index and found a general way to calculate the direction-dependent refractive index and the condition for zero index in a given direction. By analogy with linear versus circular polarization, they showed that when the zero-index direction is complex-valued, a material supports waves that can propagate in only one sense, for example, clockwise. They showed that there is an infinite family of both time-reversible and time-irreversible homogeneous electromagnetic media that support unidirectional propagation for a particular polarization. The work extends the concept of the refractive index, shedding new light on […]