EurekAlert December 4, 2020 To directly convert visible light with wavelengths longer than 400 nm into higher-energy ultraviolet light researchers in Japan focused on triplet-triplet annihilation where triplets are formed on molecules following absorption of visible light. These “donor” molecules then give their triplets to “acceptor” molecules that can combine two triplets to create a single, higher-energy state that is released as ultraviolet light. They developed an acceptor molecule TIPS-naphthalene that has a high triplet-triplet-annihilation efficiency and a low enough triplet energy to easily accept triplets from a molecule called Ir(C6)2(acac). The combination of TIPS-naphthalene and Ir(C6)2(acac) successfully achieved the […]
Tag Archives: Photonics
Infrared light antenna powers molecular motor
EurekAlert October 28, 2020 Light-controlled molecular motors can be used to create functional materials, to provide autonomous motion or in systems that can respond on command. An international team of researchers (the Netherlands, Switzerland, Germany) designed a rotary motor that is efficiently powered by near-infrared light, through adding an antenna to the motor molecule. Through a covalent bond, the motor molecule was linked to an ‘antenna’, which can absorb two near-infrared photons. The resulting excitation of the antenna is then passed on to the motor part of the molecule. For the system to work, the energy levels of the antenna […]
Well-formed disorder for versatile light technologies
Nanowerk October 13, 2020 In nonlinear crystals, two photons of a particular frequency can be turned into one photon having twice that frequency if they are phase matched. This often severely limits practical applications. Researchers in Switzerland combined resonances and disorder by implementing random quasi-phase-matching in Mie resonant spheres of a few micrometres realized by the bottom-up assembly of barium titanate nanocrystals. The measured second-harmonic generation reveals a combination of broadband and resonant wave mixing, in which Mie resonances drive and enhance the second-harmonic generation, while the disorder keeps the phase-matching conditions relaxed. The nanocrystal assemblies provide new opportunities for […]
A novel approach produces a completely new kind of dynamic light structure
Phys.org August 24, 2020 At a given distance light can dynamically rotate around its center and revolve around another central axis. An international team of researchers (USA – UCSF, Naval Information Warfare Center, University of Rochester, Israel) has shown that combining twisted light and frequency combs together can produce an even more novel structure of light. The beams they simulated achieved mode purity up to 99%, and also had control of the helical phase front. The findings shed insight on our basic understanding of light generation and propagation. This innovation may have future applications in sensing, imaging, manufacturing, and metrology. […]
Photonics researchers report breakthrough in miniaturizing light-based chips
Nanowerk August 27, 2020 Researchers at the University of Rochester made an important step towards miniaturizing functional components on thin-film lithium niobate (LN) platform by developing high-speed LN electro-optic modulators, based upon photonic crystal nanobeam resonators. The devices exhibit a significant tuning efficiency, broad modulation bandwidth of 17.5 GHz, all with a tiny electro-optic modal volume. The modulators enable efficient electro-optic driving of high-Q photonic cavity modes in both adiabatic and non-adiabatic regimes and allow electro-optic switching at 11 Gb s−1 with a bit-switching energy as low as 22 fJ. The demonstration provides a crucial foundation for realizing large-scale LN […]
Scientists apply ‘twistronics’ to light propagation and make a breakthrough discovery
Nanowerk June 11, 2020 As recent research showed how superconductivity is achieved in a pair of stacked graphene layers that were rotated to the “magic twist angle” and careful control of rotational symmetries can unveil unexpected material responses. Now an international team of researchers (Singapore, USA – City University of New York, Australia, China) has discovered that an analogous principle can be applied to manipulate light in highly unusual ways. They stacked two thin sheets of molybdenum trioxide and rotated one of the layers with respect to the other. When the materials were excited by a tiny optical emitter, they […]
Quantum researchers able to split one photon into three
Phys.org February 27, 2020 By splitting one “pump photon” into two daughter photons, SPDC has had a crucial role in fundamental tests of quantum theory as well as many applications in quantum information processing. An international team of researchers (Canada, Spain, Sweden) used a flux-pumped, superconducting parametric resonator to split one microwave photon into three daughter photons. The triplet source is bright, producing a propagating photon flux comparable to ordinary two-photon SPDC. They clearly saw strong three-photon correlations in the output photons, even in the absence of normal two-photon correlations. The symmetry properties of these correlations allowed them to “fingerprint” […]
Electronics at the speed of light
EurekAlert December 23, 2019 The experimental set-up used by an international team of researchers (Germany, Spain, France, Luxembourg) involved nanoscale gold antennae as well as an ultrafast laser capable of emitting one hundred million single-cycle light pulses per second in order to generate a measurable current. The bowtie design of the optical antenna allowed for a sub-wavelength and sub-cycle spatio-temporal concentration of the electric field of the laser pulse into the gap of a width of six nm. As a result of the highly nonlinear character of electron tunneling out of the metal and acceleration over the gap in the […]
New photonics breakthrough
Science Daily December 13, 2019 An international team of researchers (USA – City College of New York, Russia) has shown that long-range interactions in the metamaterial changes the common behavior of light waves forcing them to localize in space. The study shows that by controlling the degree of such interactions one can switch between trapped and extended (propagating) character of optical waves. The new approach to trap light allows the design of new types of optical resonators, which may have significant impact on antennas in smartphones and Wi-Fi routers, and optical chips in optoelectronics used for transferring data over the […]
Creating different kinds of light with manipulable quantum properties
Science Daily September 27, 2019 An international team of researchers (Louisiana State University, NIST, Mexico, Germany) experimentally demonstrated that the manipulation of the quantum electromagnetic fluctuations of two-mode squeezed vacuum states leads to a family of quantum-correlated multiphoton states with tunable mean photon numbers and degree of correlation. The technique relies on the use of conditional measurements to engineer the excitation mode of the field through the simultaneous subtraction of photons from two-mode squeezed vacuum states. They demonstrated the engineering of a quantum state of light with up to ten photons which is an important step towards the generation of […]