By drilling holes into a thin two-dimensional sheet of hexagonal boron nitride with a gallium-focused ion beam, University of Oregon scientists have created artificial atoms that generate single photons.
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The artificial atoms - which work in air and at room temperature - may be a big step in efforts to develop all-optical quantum computing, said UO physicist Benjamín J. Alemán, principal investigator of a study published in the journal Nano Letters.
“Our work provides a source of single photons that could act as carriers of quantum information or as qubits. We’ve patterned these sources, creating as many as we want, where we want,” said Alemán, a member of the UO’s Material Science Institute and Center for Optical, Molecular, and Quantum Science. “We’d like to pattern these single photon emitters into circuits or networks on a microchip so they can talk to each other, or to other existing qubits, like solid-state spins or superconducting circuit qubits.”
In every modern microcircuit hidden inside a laptop or smartphone, you can see transistors—small semiconductor devices that control the flow of electric current, i.e. the flow of electrons. If we replace electrons with photons (elementary particles of light), then scientists will have the prospect of creating new computing systems that can process massive information flows at a speed close to the speed of light. At present, it is photons that are considered the best for transmitting information in quantum computers. These are still hypothetical computers that live according to the laws of the quantum world and are able to solve some problems more efficiently than the most powerful supercomputers.
Although there are no fundamental limits for creating quantum computers, scientists still have not chosen what material platform will be the most convenient and effective for implementing the idea of a quantum computer. Superconducting circuits, cold atoms, ions, defects in diamond and other systems now compete for being one chosen for the future quantum computer. It has become possible to put forward the semiconductor platform and two-dimensional crystals, specifically, thanks to scientists from: the University of Würzburg (Germany); the University of Southampton (United Kingdom); the University of Grenoble Alpes (France); the University of Arizona (USA); the Westlake university (China), the Ioffe Physical Technical Institute of the Russian Academy of Sciences; and St Petersburg University.
A team of researchers led by Professors Hong Zhang (photonic nanochemistry) and Evert Jan Meijer (computational chemistry) of the University of Amsterdam’s Van ’t Hoff Institute for Molecular Sciences has significantly improved the fundamental understanding of photon upconversion in nanoparticles. Through the collaborative approach of advanced spectroscopy and theoretical modelling they were able to establish that the migration of excitation energy greatly affects the upconversion dynamics. In a recent publication in Angewandte Chemie the researchers describe how ‘dopant ions spatially separated’ (DISS) nanostructures can be used for tailoring the upconversion dynamics.
Upconversion is a process in which one photon is emitted upon absorption of several photons of lower energy. It thus 'jacks’ the light from lower to higher frequencies. Typically upconversion materials are doped with lanthanide ions. These are able to shift the near infrared (NIR) light of an economic continuous wave milliwatt laser towards higher, visible frequencies and even into the ultraviolet (UV) spectral region. Potential applications in super resolution spectroscopy, high density data storage, anti-counterfeiting and biological imaging and photo-induced therapy.
Upconversion luminescence dynamics has long been believed to be determined solely by the emitting ions and their interactions with neighbouring sensitizing ions. The current research shows that this does not hold for nanostructures. Zhang, Meijer and co-workers demonstrate that in nanocrystals the luminescence time behaviour is seriously affected by the migration process of the excitation energy.
Time‑correlated single‑photon counting (TCSPC) technique is a powerful way to measure the weak light signals. The basic principle behind TCSPC is the photoelectric effect in which an electrical charge is released by absorbing a photon. Compared to the traditional strategy of detecting analog photogenerated voltage, the TCSPC technique counts the single electron pulse created by single photons, which means its sensitivity can be up to single-photon level as its name implies. In fact, the TCSPC technique has been successfully employed to detect the transient/burst photoluminescence (PL) in many research fields, and the transient spectrometer is common equipment in many labs.
Dr. Xianfeng Qiao and Prof. Dongge Ma at South China University of Technology (SCUT), China, are interested in device physics of organic optoelectronics/spintronics devices. Specifically, they pay attention to both transient PL and electroluminescence (EL) profiles, which together provide a wealth of information about how devices work.
I found these images lying around. I drew them in undergrad for an assignment to make a series of images relating to a quote.
I chose to do the quote “all we are is light made solid.” It’s an anonymous quote and I have no idea what was the intended meaning, so I chose to interpret it as a reference to photosynthesis.
According to quantum electrodynamics, the electromagnetic force is due to virtual photons, so that is another way you could interpret the quote in a science-y way.
calm day today, copied my waves hl content notes onto my notebook as a way of review, and i also had my regular two hours of math today!! just doing sinusoidal waves, and my coffee tasted delicious <3
school starts again tomorrow and i’m prepared to hit the ground sprinting because… ib
“Walking home at night, I shine my flashlight up at the sky. I send billions of … photons toward space. What is their destination? A tiny fraction will be absorbed by the air. An even smaller fraction will be intercepted by the surface of planets and stars. The vast majority … will plod on forever. After some thousands of years they will leave our galaxy; after some millions of years they will leave our supercluster. They will wander through an even emptier, even colder realm. The universe is transparent in the direction of the future."
“An elegant demonstration of a fundamental property of nature.“
Paul-Antoine Moreau said this about the first ever photo of quantum entanglement, a phenomenon so strange that Einstein called it “spooky action at a distance.”
Quantum entanglement occurs when two particles become inextricably linked, and even when separated— whatever happens to one immediately affects the other, regardless of the distance between them (hence Einstein’s description).
But I feel like these same words could be said about a waterfall, an elegant demonstration of the fundamental and bizarre properties of water, which we still don’t fully understand.
If you haven’t already seen it, the photo by Moreau and his team shows entanglement between two photons - two light particles. They’re interacting and - for a brief moment - sharing physical states.
Scientists slow down the speed of light travelling in free space|ScienceDaily
Scientists have long known that the speed of light can be slowed slightly as it travels through materials such as water or glass.
However, it has generally been thought impossible for particles of light, known as photons, to be slowed as they travel through free space, unimpeded by interactions with any materials.
In a new paper published in Science Express today (Friday 23 January), researchers from the University of Glasgow and Heriot-Watt University describe how they have managed to slow photons in free space for the first time. They have demonstrated that applying a mask to an optical beam to give photons a spatial structure can reduce their speed.
