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Tidal disruption events (TDEs) are bursts of electromagnetic energy that are released when supermassive black holes at the centres of galaxies violently disrupt a star that passes too close 1 . TDEs provide a window through which to study accretion onto supermassive black holes; in some rare cases, this accretion leads to launching of a relativistic jet 2 – 9 , but the necessary conditions are not fully understood. The best-studied jetted TDE so far is Swift J1644+57, which was discovered in γ-rays, but was too obscured by dust to be seen at optical wavelengths. Here we report the optical detection of AT2022cmc, a rapidly fading source at cosmological distance (redshift z  = 1.19325) the unique light curve of which transitioned into a luminous plateau within days. Observations of a bright counterpart at other wavelengths, including X-ray, submillimetre and radio, supports the interpretation of AT2022cmc as a jetted TDE containing a synchrotron ‘afterglow’, probably launched by a supermassive black hole with spin greater than approximately 0.3. Using four years of Zwicky Transient Facility 10 survey data, we calculate a rate of 0.0 2 − 0.01 + 0.04 Gpc −3 yr −1 for on-axis jetted TDEs on the basis of the luminous, fast-fading red component, thus providing a measurement complementary to the rates derived from X-ray and radio observations 11 . Correcting for the beaming angle effects, this rate confirms that approximately 1 per cent of TDEs have relativistic jets. Optical surveys can use AT2022cmc as a prototype to unveil a population of jetted TDEs. A series of early-time, multiwavelength observations of an optical transient, AT2022cmc, indicate that it is a relativistic jet from a tidal disruption event originating from a supermassive black hole.

Development of scalable quantum photonic technologies requires on-chip integration of photonic components. Recently, hexagonal boron nitride (hBN) has emerged as a promising platform, following reports of hyperbolic phonon-polaritons and optically stable, ultra-bright quantum emitters. However, exploitation of hBN in scalable, on-chip nanophotonic circuits and cavity quantum electrodynamics (QED) experiments requires robust techniques for the fabrication of high-quality optical resonators. In this letter, we design and engineer suspended photonic crystal cavities from hBN and demonstrate quality ( Q ) factors in excess of 2000. Subsequently, we show deterministic, iterative tuning of individual cavities by direct-write EBIE without significant degradation of the Q -factor. The demonstration of tunable cavities made from hBN is an unprecedented advance in nanophotonics based on van der Waals materials. Our results and hBN processing methods open up promising avenues for solid-state systems with applications in integrated quantum photonics, polaritonics and cavity QED experiments. Hexagonal boron nitride (hBN) is a layered van der Waals material showing promise for nanophotonics. Here, the authors design hBN photonic crystal cavities with quality factors exceeding 2000, and further demonstrate deterministic tuning of individual cavities by minimally-invasive electron beam induced etching.

PLATO (PLAnetary Transits and Oscillations of stars) is ESA’s M3 mission designed to detect and characterise extrasolar planets and perform asteroseismic monitoring of a large number of stars. PLATO will detect small planets (down to <2R Earth ) around bright stars (<11 mag), including terrestrial planets in the habitable zone of solar-like stars. With the complement of radial velocity observations from the ground, planets will be characterised for their radius, mass, and age with high accuracy (5%, 10%, 10% for an Earth-Sun combination respectively). PLATO will provide us with a large-scale catalogue of well-characterised small planets up to intermediate orbital periods, relevant for a meaningful comparison to planet formation theories and to better understand planet evolution. It will make possible comparative exoplanetology to place our Solar System planets in a broader context. In parallel, PLATO will study (host) stars using asteroseismology, allowing us to determine the stellar properties with high accuracy, substantially enhancing our knowledge of stellar structure and evolution. The payload instrument consists of 26 cameras with 12cm aperture each. For at least four years, the mission will perform high-precision photometric measurements. Here we review the science objectives, present PLATO‘s target samples and fields, provide an overview of expected core science performance as well as a description of the instrument and the mission profile towards the end of the serial production of the flight cameras. PLATO is scheduled for a launch date end 2026. This overview therefore provides a summary of the mission to the community in preparation of the upcoming operational phases.

Aqueous alkaline batteries see bright future in renewable energy storage and utilization, but their practical application is greatly challenged by the unsatisfactory performance of anode materials. Herein, we demonstrate a latent Sb stripping/plating chemistry by constructing an oxygen-rich interface on carbon substrate, thus providing a decent anode candidate. The functional interface effectively lowers the nucleation overpotential of Sb and strengthens the absorption capability of the charge carriers (SbO 2 − ions). These two advantageous properties inhibit the occurrence of side reactions and thus enable highly reversible Sb stripping/plating. Consequently, the Sb anode delivers theoretical-value-close specific capacity (627.1 mA h g −1 ), high depth of discharge (95.0%) and maintains 92.4% coulombic efficiency over 1000 cycles. A robust aqueous NiCo 2 O 4 //Sb device with high energy density and prominent durability is also demonstrated. This work provides a train of thoughts for the development of aqueous alkaline batteries based on Sb chemistry. The practical application of aqueous alkaline battery is confined by limited choice of anode. Here, the authors demonstrate an oxygen-rich interface induced reversible Sb stripping/plating chemistry that provides a promising Sb metal anode with fast reaction kinetics and favourable stability.

Functional imaging using fluorescent indicators has revolutionized biology, but additional sensor scaffolds are needed to access properties such as bright, far-red emission. Here, we introduce a new platform for ‘chemigenetic’ fluorescent indicators, utilizing the self-labeling HaloTag protein conjugated to environmentally sensitive synthetic fluorophores. We solve a crystal structure of HaloTag bound to a rhodamine dye ligand to guide engineering efforts to modulate the dye environment. We show that fusion of HaloTag with protein sensor domains that undergo conformational changes near the bound dye results in large and rapid changes in fluorescence output. This generalizable approach affords bright, far-red calcium and voltage sensors with highly tunable photophysical and chemical properties, which can reliably detect single action potentials in cultured neurons. Combining the self-labeling HaloTag protein with synthetic environmentally sensitive fluorophores provides a platform for the construction of bright, far-red fluorescent calcium and voltage sensors with tunable photophysical and chemical properties.

Perovskite crystals—with their exceptional nonlinear optical properties, lasing and waveguiding capabilities—offer a promising platform for integrated photonic circuitry within the strong-coupling regime at room temperature. Here we demonstrate a versatile template-assisted method to efficiently fabricate large-scale waveguiding perovskite crystals of arbitrarily predefined geometry such as microwires, couplers and splitters. We non-resonantly stimulate a condensate of waveguided exciton–polaritons resulting in bright polariton lasing from the transverse interfaces and corners of our perovskite microstructures. Large blueshifts with excitation power and high mutual coherence between the different edge and corner lasing signals are detected in the far-field photoluminescence, implying that a spatially extended condensates of coherent polaritons has formed. The condensate polaritons are found to propagate over long distances in the wires from the excitation spot and can couple to neighbouring wires through large air gaps, making our platform promising for integrated polaritonic circuitry and on-chip optical devices with strong nonlinearities. A method to fabricate arbitrarily shaped perovskite crystals is measured, apt for the realization of integrated photonic circuitry, demonstrating room-temperature waveguided exciton–polariton condensation and bright polariton edge lasing.

Quantum fluctuations disrupt the cyclic motions of dissipative Kerr solitons (DKSs) in nonlinear optical microresonators and consequently cause timing jitter of the emitted pulse trains. This problem is translated to the performance of several applications that employ DKSs as compact frequency comb sources. Recently, device manufacturing and noise reduction technologies have advanced to unveil the quantum properties of DKSs. Here we investigate the quantum decoherence of DKSs existing in normal-dispersion microresonators known as dark pulses. By virtue of the very large material nonlinearity, we directly observe the quantum decoherence of dark pulses in an AlGaAs-on-insulator microresonator, and the underlying dynamical processes are resolved by injecting stochastic photons into the microresonators. Moreover, phase correlation measurements show that the uniformity of comb spacing of quantum-limited dark pulses is better than 1.2 × 10 −16 and 2.5 × 10 −13 when normalized to the optical carrier frequencies and repetition frequencies, respectively. Comparing DKSs generated in different material platforms explicitly confirms the advantages of dark pulses over bright solitons in terms of quantum-limited coherence. Our work establishes a critical performance assessment of DKSs, providing guidelines for coherence engineering of chip-scale optical frequency combs. Authors report quantum decoherence of dissipative Kerr solitons in normal-dispersion microresonators, also known as dark pulses. They show the quantum decoherence of dark pulses and their potential advantages over bright solitons in an AlGaAs-on-insulator system.

Soliton microcombs are helping to advance the miniaturization of a range of comb systems. These combs mode lock through the formation of short temporal pulses in anomalous dispersion resonators. Here, a new microcomb is demonstrated that mode locks through the formation of pulse pairs in coupled normal dispersion resonators. Unlike conventional microcombs, pulses in this system cannot exist alone, and instead phase lock in pairs wherein pulses in each pair feature different optical spectra. The pairwise mode-locking modality extends to multiple pulse pairs and beyond two rings, and it greatly constrains mode-locking states. Two- (bipartite) and three-ring (tripartite) states containing many pulse pairs are demonstrated, including crystal states. Pulse pairs can also form at recurring spectral windows. We obtained the results using an ultra-low-loss Si3N4 platform that has not previously produced bright solitons on account of its inherent normal dispersion. The ability to generate multicolour pulse pairs over multiple rings is an important new feature for microcombs. It can extend the concept of all-optical soliton buffers and memories to multiple storage rings that multiplex pulses with respect to soliton colour and that are spatially addressable. The results also suggest a new platform for the study of topological photonics and quantum combs.Bright solitons are produced through the interaction of pulse pairs generated via a continuous-wave fibre laser, which pumps two coupled microresonators featuring normal dispersion. Multicolour pulse pairs over multiple rings can also be generated, of great promise for applications such as all-optical soliton buffers and memories, study of quantum combs and topological photonics.

Intrinsically directional light emitters are potentially important for applications in photonics including lasing and energy-efficient display technology. Here, we propose a new route to overcome intrinsic efficiency limitations in light-emitting devices by studying a CdSe nanoplatelets monolayer that exhibits strongly anisotropic, directed photoluminescence. Analysis of the two-dimensional k -space distribution reveals the underlying internal transition dipole distribution. The observed directed emission is related to the anisotropy of the electronic Bloch states governing the exciton transition dipole moment and forming a bright plane. The strongly directed emission perpendicular to the platelet is further enhanced by the optical local density of states and local fields. In contrast to the emission directionality, the off-resonant absorption into the energetically higher 2D-continuum of states is isotropic. These contrasting optical properties make the oriented CdSe nanoplatelets, or superstructures of parallel-oriented platelets, an interesting and potentially useful class of semiconductor-based emitters. Strong anisotropy of the electronic Bloch functions observed in CdSe nanoplatelets enables efficient directional emission.

Single-photon emitters serve as building blocks for many emerging concepts in quantum photonics. The recent identification of bright, tunable and stable emitters in hexagonal boron nitride (hBN) has opened the door to quantum platforms operating across the infrared to ultraviolet spectrum. Although it is widely acknowledged that defects are responsible for single-photon emitters in hBN, crucial details regarding their origin, electronic levels and orbital involvement remain unknown. Here we employ a combination of resonant inelastic X-ray scattering and photoluminescence spectroscopy in defective hBN, unveiling an elementary excitation at 285 meV that gives rise to a plethora of harmonics correlated with single-photon emitters. We discuss the importance of N π* anti-bonding orbitals in shaping the electronic states of the emitters. The discovery of elementary excitations in hBN provides fundamental insights into quantum emission in low-dimensional materials, paving the way for future investigations in other platforms. Combining resonant inelastic X-ray scattering and photoluminescence spectroscopy, an elementary excitation in hexagonal-boron-nitride-based single-photon emitters has been demonstrated, giving rise to multiple regular harmonics that can explain the wide frequency range of these emitters.