Nature Photonics最新文献

Laser sources power ultrafast data transmission, computing acceleration, access to ultra-high-speed signalling, and sensing applications such as chemical detection, distance measurements and pattern recognition. The ever-growing scale of these applications drives innovation in multiwavelength lasers for massively parallel processing. We report a nanophotonic Kerr-resonator circuit that converts the power of an input laser into a normal-dispersion soliton frequency comb at approaching unit efficiency. By coupling forward and backward propagation, we realize a bidirectional Kerr resonator that supports universal phase matching but also opens excess loss by double-sided emission. We therefore induce reflection of the resonator’s forward, external coupling port to favour backward propagation, resulting in efficient, unidirectional soliton formation. Coherent backscattering with nanophotonics provides the control to put arbitrary phase-matching and efficient laser power consumption on equal footing in Kerr resonators. In the overcoupled-resonator regime, we measure 65% conversion efficiency for a 40 mW input pump laser; the nonlinear circuit consumes 97% of the pump, generating the maximum possible comb power. Our work opens up high-efficiency soliton formation in integrated photonics, exploring how energy flows in nonlinear circuits and enabling laser sources for applications such as advanced transmission, computing, quantum sensing and artificial intelligence.

Three-dimensional structured illumination microscopy (3D-SIM) doubles the spatial resolution along all dimensions and is used widely in cellular imaging. However, its temporal resolution is constrained by the need for sequential plane-by-plane movement of the sample using a piezo stage for imaging, which often increases the acquisition time to several seconds per volume. To address this limitation, we develop 3D multiplane SIM (3D-MP-SIM), which simultaneously detects multiplane images and reconstructs them using synergistically evolved reconstruction algorithms. Compared with conventional 3D-SIM imaging, 3D-MP-SIM achieves an approximately eightfold increase in the temporal resolution of volumetric super-resolution imaging, with lateral and axial spatial resolutions of about 120 and 300 nm, respectively. The rapid acquisition substantially reduces motion artefacts during the imaging of dynamic structures, such as late endosomes, in live cells. Moreover, we demonstrate the capabilities of 3D-MP-SIM via high-speed time-lapse volumetric imaging of the endoplasmic reticulum at rates of up to 11 volumes per second. We also show the feasibility of dual-colour imaging by observing rapid and close interactions among intra- and intercellular organelles in 3D space. These results highlight the potential of 3D-MP-SIM for explaining dynamic behaviours and interactions at the subcellular level and in three dimensions.

Quantum confinement in monolayer semiconductors results in optical properties intricately linked to electrons, which can be manipulated by external electric fields. These optoelectronic features offer untapped potential for studying biological electrical activity. In addition to their relatively high quantum yields, picosecond level emission lifetimes make these materials particularly promising for monitoring biological voltages with high spatiotemporal resolution. Here we investigate exciton-to-trion conversion in ångström-thick semiconductors to experimentally demonstrate label-free, dual-polarity, all-optical detection of electrical activity, via changes in photoluminescence, in cardiomyocyte cultures with ultrahigh temporal resolution. We devise a physical model to demonstrate that this conversion process is inherently governed by the quantum statistics of the background electrons induced by biological activity. We show that the monolayer MoS₂ enables completely bias-free tetherless operation due to its substantial trion density originating from intrinsic sulfur vacancies introduced during chemical vapour deposition. Our work opens up an unexplored avenue of opportunities for label-free all-optical voltage sensing using ångström-thick semiconductor materials whose applications have been elusive in the biological domain. This line of thinking at the intersection of biology and quantum science could lead to the discovery of non-ubiquitous quantum materials for detection of biological electrical activity.

Quantum vortices of light carrying orbital angular momentum stand as essential resources for quantum photonic technologies. Recent advancements in integrated photonics offer the potential to create and control quantum vortices using fully integrated circuits, eliminating the need for intricate free-space alignment, modulation and the stabilization of bulky optical elements. However, generating quantum vortices in planar optical waveguides and circuits poses challenges, owing to the complexities of confining and guiding twisted photons and, importantly, the difficulties in preparing the quantum superposition and entanglement of vortex states. Here we report the realization of entangled quantum vortex emitters, leveraging programmable integrated nanophotonic circuits. These circuits enable the generation and arbitrary control of resilient vortex entanglement in free space, coherently transitioning from on-chip-created path entanglement. This capability is facilitated by a chip-to-free-space interfacing quantum technology that combines reprogrammable integrated quantum photonics with advanced classical free-space beam structuring. The emitters operate in a plug-and-play manner, enabling swift reconfiguration within microseconds. Validation of multidimensional genuine entanglement is achieved through quantum tomography and measurement of the dimension witness. Our work demonstrates integrated quantum vortex devices that combine the versatility of the on-chip processing quantum information with the robustness of transmitting quantum vortices in free space, opening new avenues for applications in quantum communication, quantum light detection and ranging, and quantum computation and storage.

Photon loss is the biggest problem for scalable photonic quantum information processing. This issue can be tackled through quantum error correction, provided that the overall photon loss is below a threshold of one-third. However, all reported on-demand and indistinguishable single-photon sources still fall short of this threshold. Here, by using tailor shaped laser pulse excitation on a high-quantum efficiency single quantum dot deterministically coupled to a tunable open microcavity, we simultaneously demonstrate a high-performance source with a low multi-photon error of g⁽²⁾(0) = 0.0205(6), photon indistinguishability of 0.9856(13) and overall system efficiency of 0.712(18). This source for the first time reaches the efficiency threshold for scalable photonic quantum computing. With this source, we further demonstrate 1.89(14) dB intensity squeezing, and consecutive 40-photon events with a count rate of 1.67 mHz.

Measurement-based quantum computing is a promising paradigm of quantum computation, in which universal computing is achieved through a sequence of local measurements. The backbone of this approach is the preparation of multipartite entanglement, known as cluster states. Although a cluster state with two-dimensional connectivity is required for universality, a three-dimensional cluster state is necessary for additionally achieving fault tolerance. However, the challenge of making three-dimensional connectivity has limited cluster state generation capability up to two dimensions. Here we demonstrate the deterministic generation of a three-dimensional cluster state based on the photonic continuous-variable platform. To realize three-dimensional connectivity, we harness a crucial advantage of time–frequency modes of ultrafast quantum light: an arbitrary complex mode basis can be accessed directly, enabling connectivity as desired. We demonstrate the versatility of our method by generating cluster states with one-, two- and three-dimensional connectivities. For their complete characterization, we develop a quantum state tomography method for multimode Gaussian states. Moreover, we verify the cluster state generation by nullifier measurements as well as full inseparability tests. Our work paves the way towards fault-tolerant and universal-measurement-based quantum computing.

The Talbot effect describes the periodic revivals of field patterns, and is ubiquitous across wave systems. In optics, it is mostly known for its manifestations in space and time, but it is also observed in the wavevector and frequency spectra owing to the Fourier duality. Recently, the Talbot self-imaging has been shown separately in the azimuthal angle and orbital angular momentum (OAM) domains. Here we reveal the missing link between them and demonstrate the generalized angle–OAM Talbot effect. Versatile transformations of petal fields and OAM spectra are experimentally demonstrated, based on the synergy of angular Talbot phase modulation and light propagation in a ring-core fibre. Moreover, the generalized self-imaging concept leads to new realizations in mode sorting, which separate OAM modes in a modulo manner, theoretically free from any crosstalk within the congruence classes of OAM modes. We design and experimentally construct various mode sorters with excellent performance, and show the unconventional behaviour of Talbot-based sorters where neighbouring OAM modes can be mapped to positions that are far apart. Besides its fundamental interest, our work has applications in OAM-based information processing, and implies that the physical phenomena in time–frequency and angle–OAM domains are broadly connected and that their processing techniques may be borrowed interchangeably.

Correction to: Nature Photonics https://doi.org/10.1038/s41566-022-01058-z, published online 25 August 2022.

Brillouin microscopy is an emerging optical elastography technique that can be used to assess mechanical properties of biological samples in a three-dimensional, all-optical and hence non-contact fashion. However, the low cross-section of spontaneous Brillouin scattering produces weak signals that often necessitate prolonged exposure times or illumination dosages that are potentially harmful for biological samples. Here we present a new approach for highly multiplexed and therefore rapid spectral acquisition of the Brillouin-scattered light. Specifically, by exploiting a custom-built Fourier-transform imaging spectrometer and the symmetric properties of the Brillouin spectrum, we experimentally demonstrate full-field 2D spectral Brillouin imaging of phantoms as well as biological samples, at a throughput of up to 40,000 spectra per second, with a precision of ~70 MHz and an effective 2D image acquisition speed of 0.1 Hz over a ~300 × 300 µm² field of view. This represents an approximately three-orders-of-magnitude improvement in speed and throughput compared with standard confocal methods, while retaining high spatial resolution and the capability to acquire three-dimensional images of photosensitive samples in biology and medicine.

Kerr microcombs have drawn substantial interest as mass-manufacturable, compact alternatives to bulk frequency combs. This could enable the deployment of many comb-reliant applications previously confined to laboratories. Particularly enticing is the prospect of microcombs performing optical frequency division in compact optical atomic clocks. Unfortunately, it is difficult to meet the self-referencing requirement of microcombs in these systems owing to the approximately terahertz repetition rates typically required for octave-spanning comb generation. In addition, it is challenging to spectrally engineer a microcomb system to align a comb mode with an atomic clock transition with a sufficient signal-to-noise ratio. Here we adopt a Vernier dual-microcomb scheme for optical frequency division of a stabilized ultranarrow-linewidth continuous-wave laser at 871 nm to an ~235 MHz output frequency. This scheme enables shifting an ultrahigh-frequency (~100 GHz) carrier-envelope offset beat down to frequencies where detection is possible and simultaneously placing a comb line close to the 871 nm laser—tuned so that, if frequency doubled, it would fall close to the clock transition in ¹⁷¹Yb⁺. Our dual-comb system can potentially combine with an integrated ion trap towards future chip-scale optical atomic clocks.