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The explorations of physical degrees of freedom with infinite dimensionalities, such as orbital angular momentum and frequency of light, have profoundly reshaped the landscape of modern optics with representative photonic functional devices including optical vortex emitters and frequency combs. In nanophotonics, whisper gallery mode microresonators naturally support orbital angular momentum of light and have been demonstrated as on-chip emitters of monochromatic optical vortices. On the other hand, whisper gallery mode microresonators serve as a highly-efficient nonlinear optical platform for producing light at different frequencies - i.e., microcombs. Here, we interlace the optical vortices and microcombs by demonstrating an optical vortex comb on an III-V integrated nonlinear microresonator. The angular-grating-dressed nonlinear microring simultaneously emits up to 50 orbital angular momentum modes that are each spectrally addressed to the frequency components ((longitudinal whispering gallery modes) of the generated microcomb. We further show that the integrated vortex comb with varied orbital angular momenta distributed across different frequencies exhibits unprecedented advantages in the synthesis of spatio-temporal optical pulses with time-varying orbital angular momenta. This work may immediately boost the development of integrated nonlinear/quantum photonics for exploring fundamental optical physics and advancing photonic quantum technology., 6 pages, 4 figures, comments are welcome. SI is available upon on requests

A single quantum dot (QD) strongly coupled with a plasmonic nanoparticle yields a promising qubit for scalable solid-state quantum information processing at room temperature. However, realizing such a strong coupling remains challenging due to the difficulty of spatial overlap of the QD excitons with the plasmonic electric fields (EFs). Here, by using a transmission electron microscope we demonstrate for the first time that this overlap can be realized by integrating a deterministic single QD with a single Au nanorod. When a wedge nanogap cavity consisting of them and the substrate is constructed, the plasmonic EFs can be more effectively "dragged" and highly confined in the QD's nanoshell where the excitons mainly reside. With these advantages, we observed the largest spectral Rabi splitting (reported so far) of ∼234 meV for a single QD strong coupling with plasmons. Our work opens a pathway to the massive construction of room-temperature strong coupling solid qubits.

It can solve the disadvantages of traditional crop biochemical parameters measurement methods on combining hyperspectral technology with machine learning technology to retrieve crop growth index. Four nitrogen application levels were set by taking rice varieties Zhuliangyou 819 and Zhuliangyou 39 as materials. Through the rice test in 2020, the spectral data of rice leaves at different growth stages and their corresponding SPAD values and nitrogen contents were collected. Savitzky-Golay Smoothing (SG), Standard Normal Variable (SNV), Principal Component Analysis (PCA) and Multiplicative Scattering Correction (MSC) were used to preprocess spectral reflectance. Three classifiers, Support Vector Machine (SVM), Partial Least Squares Regression (PLSR) and Random Forest (RF) were used to build the model. The results showed that SG-PLSR combination had the highest accuracy in predicting chlorophyll and nitrogen in double-cropping rice. The test results provide a good reference for other indexes of rice.

Employing nanostructure to generate large chiroptical response has been cultivated as an emerging field, for its great potentials in integrated optics, biochemistry detections, etc. However, the lack of intuitive approaches for analytically describing the chiroptical nanoparticles has discouraged researchers from effectively designing advanced chiroptical structures. In this work, we take the twisted nanorod dimer system as a basic example to provide an analytical approach from the perspective of mode coupling, including far-field coupling and near-field coupling of nanoparticles. Using this approach, we can calculate the expression of circular dichroism (CD) in the twisted nanorod dimer system, which can establish the analytical relationship between the chiroptical response and the basic parameters of this system. Our results show that the CD response can be engineered by modulating the structure parameters, and a high CD response of ∼ 0.78 under the guidance of this approach has been achieved.

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.

High-performance solid-state quantum sources in the telecom band are of paramount importance for long-distance 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/GaAs 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 InAs growth rate and an InGaAs 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.

Background To investigate the relationships of monocyte to high-density lipoprotein cholesterol (HDL-C) ratio (MHR) with left ventricular hypertrophy (LVH) in young and middle-aged patients with essential hypertension (EH). Methods A retrospective analysis was performed on clinical data of 294 young and middle-aged patients with EH (aged from 18 to 65 years old). According to the left ventricular mass index (LVMI), the patients were divided into LVH (n = 98) and non-LVH (n = 196) groups. The data on echocardiography, routine blood test, biochemical examination, and so on were collected in all subjects, then LVMI and MHR were calculated. The association between MHR and hypertensive LVH was analyzed by correlation and binary logistic regression analyses. The receiver operating characteristic curve (ROC) was used to determine the predict value of MHR. Results MHR was higher while HDL-C was lower in the LVH group compared with the non-LVH group (MHR: 0.47 ± 0.11 vs. 0.33 ± 0.12, P < 0.001; HDL-C: 1.05 [0.94–1.22] vs. 1.27 [1.07–1.47] mmol/l, P < 0.001). Correlation analysis showed that LVMI was positively correlated with MHR (r = 0.381, P < 0.001). Multivariate logistic regression analysis showed that MHR was an independent risk factor for LVH in young and middle-aged EH patients (odds ratio = 2.914, 95% confidence interval [CI] 2.084–4.068, P < 0.001) after adjusting for body mass index, smoking, HDL-C, and other confounding factors. The area under the ROC curve of MHR for predict LVH was 0.831 (95% CI 0.782–0.880), and the optimal cutoff value of MHR was 0.37, with a sensitivity of 93.9% and a specificity of 75.5%. Conclusions MHR is positively correlated with LVH in young and middle-aged patients with EH. MHR is an independent risk factor for LVH in this population, and can be used for LVH risk screening.

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.