Granulocytic sarcoma with long spinal cord compression:A case report

BACKGROUND As an extramedullary form of proliferating myeloblasts,granulocytic sarcoma(GS)is common in patients with acute myeloid leukemia.GS in the central nervous system is rare,and an intraspinal space-occupying lesion caused by GS is even rarer.Surgical decompression is often necessary to remove the intraspinal space-occupying lesion.To the best of our knowledge,we report,for the first time a case of GS that caused extensive compression in the spinal canal without surgical decompression treatment.CASE SUMMARY A 15-year-old male suddenly developed numbness and weakness in his lower limbs for 10 d,which affected his walking ability.Acute myeloid leukemia was later diagnosed in the Department of Hematology.Magnetic resonance imaging revealed that multiple segmental space-occupying lesions were causing severe spinal cord compression in the thoracic spinal canal.As a result,the patient received routine chemotherapy before surgery.Interestingly,the intraspinal space-occupying lesions completely diminished on magnetic resonance imaging after a course of chemotherapy,and the sensation and strength in his lower limbs markedly recovered.CONCLUSION An intraspinal space-occupying lesion could be the first symptom of acute myeloid leukemia,causing spinal nerve compression without any other symptoms.Following standard chemotherapy,spinal canal compression can be quickly relieved,and the spinal cord and nerve function restored,avoiding emergency surgery.

Optical scattering imaging with sub-nanometer precision based on position-ultra-sensitive giant Lamb shift

The Lamb shift of a quantum emitter in close proximity to a plasmonic nanostructure can be three or more orders of magnitude larger than that in the free space and is ultra-sensitive to the emitter position and polarization.We demonstrate that this large Lamb shift can be sensitively observed from the scattering or absorption spectrum dip shift of the coupled system when the plasmonic nanoparticle or tip scans the emitter.Using these observations,we propose a scanning optical scattering imaging method based on the plasmonic-enhanced Lamb shift with achieves sub-nanometer resolution.Our method is based on the scattering or absorption spectrum of the plasmon-emitter coupling system,which is free of the fluorescence quenching problem and easier to implement in a plasmon-emitter coupling system.In addition,our scheme works even if the quantum emitter is slightly below the dielectric surface,which can bring about broader applications,such as detecting atoms and molecules or quantum dots above or under a surface.

Strong light–matter interactions based on excitons and the abnormal all-dielectric anapole mode with both large field enhancement and low loss

The room temperature strong coupling between the photonic modes of micro/nanocavities and quantum emitters(QEs) can bring about promising advantages for fundamental and applied physics.Improving the electric fields(EFs) by using plasmonic modes and reducing their losses by applying dielectric nanocavities are widely employed approaches to achieve room temperature strong coupling.However,ideal photonic modes with both large EFs and low loss have been lacking.Herein,we propose the abnormal anapole mode (AAM),showing both a strong EF enhancement of~70-fold (comparable to plasmonic modes) and a low loss of 34 meV,which is much smaller than previous records of isolated all-dielectric nanocavities.Besides realizing strong coupling,we further show that by replacing the normal anapole mode with the AAM,the lasing threshold of the AAM-coupled QEs can be reduced by one order of magnitude,implying a vital step toward on-chip integration of nanophotonic devices.

Reshaping plasmon modes by film interference

Localized surface plasmon resonances(LSPRs)in metal nanostructures have been a central subject of nano-photonics due to their ability to manipulate light beyond the optical diffraction limit.Nevertheless,the large intrinsic dissipations of LSPRs have severely hindered their applications,so the on-demand control of the LSPR modes is highly desired and remains open yet.Here,we experimentally and theoretically demonstrate that the plasmon mode can be effectively engineered by interacting with constructive or destructive modes supported by film interference.When a metal nanoparticle interacts with a constructive mode,the dissipation linewidth of its LSPR mode shows a significant reduction of 58%.Simultaneously,the scattering intensity is remarkably enhanced,in vast favor of measuring weak signals from small nanoparticles.Furthermore,the film-destructiveinterference splitting in the scattering spectrum by weak coupling,rather than strong coupling,is revealed if the plasmon particles interact with the destructive mode,resulting in two new hybrid plasmon modes with narrow linewidths.The effective polarizability model of reshaping the LSPR modes by the film interference is present to well understand the experimental observations.Our work may pave the way toward low-loss plasmonic photonics and its practical applications.

Full-colour nanoprint-hologram synchronous metasurface with arbitrary hue-saturationbrightness control

The colour gamut,a two-dimensional(2D)colour space primarily comprising hue and saturation(HS),lays the most important foundation for the colour display and printing industries.Recently,the metasurface has been considered a promising paradigm for nanoprinting and holographic imaging,demonstrating a subwavelength image resolution,a flat profile,high durability,and multi-functionalities.Much effort has been devoted to broaden the 2D HS plane,also known as the CIE map.However,the brightness(B),as the carrier of chiaroscuro information,has long been neglected in metasurface-based nanoprinting or holograms due to the challenge in realising arbitrary and simultaneous control of full-colour HSB tuning in a passive device.Here,we report a dielectric metasurface made of crystal silicon nanoblocks,which achieves not only tailorable coverage of the primary colours red,green and blue(RGB)but also intensity control of the individual colours.The colour gamut is hence extruded from the 2D CIE to a complete 3D HSB space.Moreover,thanks to the independent control of the RGB intensity and phase,we further show that a singlelayer silicon metasurface could simultaneously exhibit arbitrary HSB colour nanoprinting and a full-colour hologram image.Our findings open up possibilities for high-resolution and high-fidelity optical security devices as well as advanced cryptographic approaches.

Perturbative countersurveillance metaoptics with compound nanosieves

The progress of metaoptics relies on identifying photonic materials and geometries,the combination of which represents a promising approach to complex and desired optical functionalities.Material candidate options are primarily limited by natural availability.Thus,the search for meta-atom geometries,by either forward or inverse means,plays a pivotal role in achieving more sophisticated phenomena.Past efforts mainly focused on building the geometric library of individual meta-atoms and synthesizing various ones into a design.However,those efforts neglected the powerfulness of perturbative metaoptics due to the perception that perturbations are usually regarded as adverse and in need of being suppressed.Here,we report a perturbation-induced countersurveillance strategy using compound nanosieves mediated by structural and thermal perturbations.Private information can be almost perfectly concealed and camouflaged by the induced thermal-spectral drifts,enabling information storage and exchange in a covert way.This perturbative metaoptics can self-indicate whether the hidden information has been attacked during delivery.Our results establish a perturbative paradigm of securing a safer world of information and internet of things.

Preparation and H_2S Gas-Sensing Performances of Coral-Like SnO_2–CuO Nanocomposite

Nanocomposites composed of SnO2 and CuO were prepared by hydrothermal method. The microstructures of obtained SnO2-CuO powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption test. The results show that the nanocomposites exhibited coral-like nanostructure, and the average crystalline size of SnO2 was 12 nm. The specific surface area of the four samples, SnO2- 0.2CuO, SnO2-0.5CuO, SnO2-1.0CuO and SnO2-2.0CuO are 72.97, 58.77, 49.72 and 54.95 m2/g, respectively. The gas sensing performance of the four samples to ethanol, formaldehyde and H2S was studied. The sensor of SnOa-0.5CuO exhibited high response to hydrogen sulfide （4173 to 10 ppm H2S, where ppm represent 10-6）, and low response to ethanol and formaldehyde. The good selectivity exhibited that the SnO2-0.5CuO nanocomposite can be a promising candidate for highly sensitive and selective gas-sensing material to H2S.

Dual effects of disorder on the strongly-coupled system composed of a single quantum dot and a photonic crystal L3 cavity

Light-matter interaction in the strong coupling regime enables light control at the single-photon level. We develop numerical method and analytical expressions to calculate the decay kinetics of an initially excited two-level quantum emitter in dielectric nanostructure and single-mode cavity, respectively. We use these methods to discover the dual effects of disorder on the stronglycoupled system composed of a single quantum dot and a photonic crystal L3 cavity. The quality factor is sensitive to disorder,while the g factor and vacuum Rabi splitting are robust against disorder. A small amount of disorder may either decrease or increase the light localization and the light-matter interaction. Our methods offer flexible and efficient theoretical tools for the investigation of light-matter interaction, especially cavity quantum electrodynamics. Our findings significantly lower the requirements for optimization effort and fabrication precision and open up many promising practical possibilities.

Plasmonic-photonic cavity for high-efficiency single-photon blockade

The generation and manipulation of single photons are crucial in advanced quantum technologies, such as quantum communication and quantum computation devices. High-purity single photons can be generated from classical light using the single-photon blockade(1 PB). However, the efficiency and purity are exclusive in 1 PB, which hinders its practical applications. Here, we show that the resonantly coupled plasmonic-photonic cavity can boost the efficiency of single-photon generation by more than three orders of magnitude compared with that of all-dielectric microcavity. This significant improvement is attributed to two new mechanisms of atom-microcavity coupling after introducing the plasmonic cavity: the formation of a quasi-bound state and the transition to the nonreciprocal regime, due to the destructive interference between the coupling pathways and the nonzero relative phase of the closed-loop coupling, respectively. The quasi-bound state has a relatively small decaying, while its effective coupling strength is significantly enhanced. Suppressing the dissipative component of the effective atom-microcavity coupling in the nonreciprocal regime can further improve single-photon performance, particularly without temporal oscillations. Our study demonstrates the possibility of enhancing the intrinsically low efficiency of 1 PB in low excitation regime, and unveils the novel light-matter interaction in hybrid cavities.

Bright single-photon sources in the telecom band by deterministically coupling single quantum dots to a hybrid circular Bragg resonator

High-performance solid-state quantum sources in the telecom band are of paramount importance for longdistance quantum communications and the quantum Internet by taking advantage of a low-loss optical fiber network.Here,we demonstrate bright telecom-wavelength single-photon sources based on In(Ga)As/Ga As quantum dots(QDs)deterministically coupled to hybrid circular Bragg resonators(h-CBRs)by using a wide-field fluorescence imaging technique.The QD emissions are redshifted toward the telecom O-band by using an ultra-low In As growth rate and an In Ga As strain reducing layer.Single-photon emissions under both continuous wave(CW)and pulsed operations are demonstrated,showing high brightness with count rates of 1.14 MHz and 0.34 MHz under saturation powers and single-photon purities of g^(2)(0)=0.11±0.02(CW)and g^(2)(0)=0.087±0.003(pulsed)at low excitation powers.A Purcell factor of 4.2 with a collection efficiency of 11.2%±1%at the first lens is extracted,suggesting efficient coupling between the QD and h-CBR.Our work contributes to the development of highly efficient single-photon sources in the telecom band for fiber-based quantum communication and future distributed quantum networks.

Dynamically tunable multifunctional QED platform

Solid-state quantum electrodynamics(QED) not only demonstrates basic principles of quantum physics, but also provides key support to future quantum technologies. However, the non-modifiability of the fabricated solid-state QED systems limits their flexibility and versatility in manipulating light-matter interaction, and severely hinders their practical applications. Here, we put forward an approach of multi-dimensionally manipulating light-matter interaction to realize a dynamically tunable multifunctional QED platform by combining the local light-induced refractive index modulation(LRIM) and strong dispersion characteristic of the photonic crystal(PC) waveguide. We demonstrate three significant functions of the platform as examples:switch control between weak and strong couplings on demand, distant quantum entanglement, and a directional single photon source with high brightness and efficiency. These functions are strongly robust against positioning error of the quantum emitter,and can be facilely realized only by local LRIM on one PC waveguide. Our work paves a new way for the realization of multifunctional quantum devices.

Integrable high-efficiency generation of three-photon entangled states by a single incident photon

Generation of multi-photon entangled states with high efficiency in integrated photonic quantum systems is still a big challenge. The usual three-photon generation efficiency based on the third-order nonlinear effect is extremely low. Here, we propose a scheme to generate three-photon correlated states, which are entangled states in frequency space and bound states in real space, with high efficiency. This method relies on two crucial processes.On one hand, by employing a Sagnac interferometer, an incident photon can be transformed into a symmetric superposition of the clockwise and counterclockwise modes of the Sagnac loop, which can then be perfectly absorbed by the emitter. On the other hand, the coupling strengths of the two transition paths of the emitter to the Sagnac loop are set to be equal, under which the absorbed photon can be emitted completely from the cascaded transition path due to quantum interference. By adjusting the coupling strengths among the three transition paths of the emitter and the waveguide modes, we can control the spectral entanglement and spatial separation among the three photons. Our proposal can be used to generate three-photon entangled states on demand, and the efficiency can be higher than 90% with some practical parameters, which can find important applications in integrated quantum information processing.

Scalable and highly efficient approach for an on-chip single-photon source

Integrated photonic circuits with quantum dots provide a promising route for scalable quantum chips with highly efficient photonic sources.However,unpolarized emission photons in general sacrifice half efficiency when coupling to the waveguide fundamental mode by a cross polarization technique for suppressing the excitation laser,while suspended waveguide photonics sources without polarization filters have poor scalability due to their mechanical fragility.Here,we propose a strategy for overcoming the challenge by coupling an elliptical Bragg resonator with waveguides on a solid-state base,featuring near-unity polarization efficiency and enabling on-chip pulsed resonant excitation without any polarization filters.We theoretically demonstrate that the proposed devices have outstanding performance of a single-photon source with 80%coupling efficiency into on-chip planar waveguides and an ultra-small extinction ratio of 10-11,as well as robustness against quantum dot position deviation.Our design provides a promising method for scalable quantum chips with a filter-free high-efficiency single-photon source.