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The use of a deep neural network is a promising technique for rapid hologram generation, where a suitable training dataset is vital for the reconstruct quality as well as the generalization of the model. In this Letter, we propose a deep neural network for phase hologram generation with a physics-informed training strategy based on Fourier basis functions, leading to orthonormal representations of the spatial signals. The spatial frequency characteristics of the reconstructed diffraction fields can be regulated by recombining the Fourier basis functions in the frequency domain. Numerical and optical results demonstrate that the proposed method can effectively improve the generalization of the model with high-quality reconstructions.

We demonstrate a fiber magnetic field sensor based on multimode fiber specklegrams. The magnetic field is detected by measuring the change of speckle patterns with digital correlation technology. When the magnetic induction increases by 50 mT, the response of correlation coefficient is more than 0.35. The sensitivity of the sensor is 0.00705 ${\rm{m}}{{\rm{T}}^{{\rm{ - 1}}}}$ for the magnetic field range of 50–100 mT, and the resolution is 0.284 mT. The temperature cross sensitivity is studied by establishing the sensing matrix. In addition, dynamic range expansion and magnetic field direction sensing are explored as the application extensions of this kind of sensor.

The real-time, in-line analysis of light polarization is critical in optical networks, currently suffering from complex systems with numerous bulky opto-electro-mechanical elements tandemly arranged along the optical path. Here, we design and fabricate a fiber-integrated polarimeter by vertically stacking three photodetection units based on six-layer van der Waals materials, including one bismuth selenide (Bi 2 Se 3 ) layer for power calibration, two twisted black phosphorus (BP) layers for polarization detection, and three hexagonal boron nitride (hBN) layers for encapsulation. The self-power-calibrated, self-driven, and unambiguous detection of both linearly polarized (LP) and circularly polarized (CP) light is realized by the broken symmetry–induced linear photogalvanic effects (LPGEs) and circular photogalvanic effects (CPGEs) in the two BP units. Moreover, the device enables single-pixel polarimetric imaging to acquire spatial polarization information. The ultracompact device structure, free from external optical and mechanical modules, may inspire the development of miniaturized optical and optoelectronic systems.

A universal, repeatable, and controllable integration of single-mode optical fiber and mixed-phase TiO

OBJECTIVE To investigate the efficacy of bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with Meige syndrome. MATERIALS AND METHODS Fifteen consecutive patients who underwent STN-DBS at the Peking University People's Hospital between September 2017 and June 2018 were included in this study. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) movement score and the BFMDRS disability score were obtained prior to surgery, and at specific time points after surgery. Patients' sleep status was also assessed before and after surgery. RESULTS The BFMDRS movement scores decreased from 15.3 ± 4.6 to 5.2 ± 6.2 after STN-DBS, with a mean improvement of 68.6% (p

The property of space-bandwidth product in computer holography is investigated based on phase space analysis. Optimization of the hologram in joint space-frequency domain can exert comprehensive constraints on the diffraction fields for high-quality optical reconstructions.

We present a compact holographic near-eye display system with high-quality speckle-free optical reconstructions using camera-in-the-loop (CITL) optimization with phase constraint strategy. The CITL optimization with phase constraint is used to iteratively synthesize the computer-generated holograms (CGHs) based on the in-system optical feedback. The phase constraint embedded into the whole CGH optimization process can effectively smooth the phase profile of reconstructed wave field, which helps to suppress the speckle noise caused by the phase singularities in CGH reconstruction. Numerical and optical experiments have been performed to demonstrate that the proposed method can provide speckle-free optical reconstructions with excellent image fidelity for holographic near-eye display in a compact setup.

In-line monitoring and routine inspection are essential for using and maintaining complex equipment. The simultaneous implementation of visual positioning and displacement measurement allows the accurate acquisition of characteristics, including object dimensions and mechanical vibrations, while rapidly locking the target position. However, the internal structure of equipment is frequently obscured, making direct visual inspection challenging; therefore, flexible and bendable fiber optic–based endoscopes are extremely valuable in harsh conditions. This study enables all-fiber visual displacement measurement using a single-mode fiber and an imaging fiber bundle. Based on optical triangulation and spot centers extraction method from fiber bundle images, 0.07 mm precision at a measurement distance of 40.12 mm is achieved vertically for rough objects. We demonstrate its surface reconstruction and vibration measurement functions. Factors that affect measurement accuracy, such as light source and object roughness, are also discussed.

Aiming at the difficulty of quantifying the importance of each evaluation index in power grid operation data quality evaluation, this paper proposes a key index weight calculation model based on analytic hierarchy process and entropy weight method, which distinguishes the importance of different indexes by weight. Aiming at the most prominent data abnormally problem in the evaluation of power grid operation data quality, the paper designs an abnormal data correction model based on RBF neural network under the Spark framework to realize the correction of abnormal data. Finally, the effectiveness of the method is verified by using SCADA data from a provincial dispatch center. The results show that the proposed method can effectively deal with abnormal grid operation data and has practical application value.

Recently, three successful antineutrino experiments (Daya Bay, Double Chooz, and RENO) measured the neutrino mixing angle θ13; however, significant discrepancies were found, both in the absolute flux and spectral shape. Much effort has been expended investigating the possible reasons for the discrepancies. In this paper, the change of neutrino energy spectrum with burnup is analyzed from the point of view of the change of neutrino energy spectrum with burnup. An accurate method for calculating neutrino energy spectrum is proposed. The non-equilibrium correction is studied by using this method. It is found that the non-equilibrium correction contributes not only to the energy region less than 4.0 MeV, but also to the energy region greater than 4.0 MeV, with a maximum correction of about 3%.