A power splitter with a wideband arbitrary splitting ratio, which provides flexibility and adaptability in forming photonic devices such as microring resonators and Mach–Zehnder interferometers, proves to be essential in photonic integrated circuits (PICs). We designed and fabricated a directional coupler-based power splitter with a wideband arbitrary splitting ratio and a microring resonator with a wideband uniform extinction ratio (ER) based on artificial gauge field (AGF) optimization. The neural network-aided inverse design method is applied to complete the target. Less than 0.9 dB power splitting variation and 1.6 dB ER variation have been achieved experimentally over a 100-nm bandwidth. Wideband performance, design efficiency, and device compactness are obtained by utilizing this optimization, which indicates great potential and universality in PIC applications.

Microcirculation imaging is crucial in understanding the function and health of various tissues and organs. However, conventional imaging methods suffer from fluorescence label dependency, lack of depth resolution, and quantification inaccuracy. Here, we report a light-sheet dynamic light-scattering imaging (LSH-DSI) system to overcome these shortcomings. LSH-DSI utilizes selected plane illumination for an optical sectioning, while a time-frequency analysis method retrieves blood flow velocity estimates from dynamic changes in the detected light intensity. We have performed imaging experiments with zebrafish embryos to obtain angiographs from the trunk and head regions. The results show that LSH-DSI can capture label-free tomographic images of microvasculature and three-dimensional quantitative maps of local blood flow velocities.

Confronting the escalating global challenge of counterfeit products, developing advanced anticounterfeiting materials and structures with physical unclonable functions (PUFs) has become imperative. All-optical PUFs, distinguished by their high output complexity and expansive response space, offer a promising alternative to conventional electronic counterparts. For practical authentications, the expansion of optical PUF keys usually involves intricate spatial or spectral shaping of excitation light using bulky external apparatus, which largely hinders the applications of optical PUFs. Here, we report a plasmonic PUF system based on heterogeneous nanostructures. The template-assisted shadow deposition technique was employed to adjust the morphological diversity of densely packed metal nanoparticles in individual PUFs. Transmission images were processed via a hash algorithm, and the generated PUF keys with a scalable capacity from 2875 to 243401 exhibit excellent uniqueness, randomness, and reproducibility. Furthermore, the wavelength and the polarization state of the excitation light are harnessed as two distinct expanding strategies, offering the potential for multiscenario applications via a single PUF. Overall, our reported plasmonic PUFs operated with the multidimensional expanding strategy are envisaged to serve as easy-to-integrate, easy-to-use systems and promise efficacy across a broad spectrum of applications, from anticounterfeiting to data encryption and authentication.

In recent years, many phase space distributions have been proposed, and one of the more independently interesting is the Bai distribution function (BDF). The BDF has been shown to interpolate between the instantaneous auto-correlation function and the Wigner distribution function, and be applied in linear frequency modulated signal parameter estimation and optical partial coherence areas. Currently, the BDF is only defined for continuous signals. However, for both simulation and experimental purposes, the signals must be discrete. This necessitates the development of a BDF analysis workflow for discrete signals. In this work, we analyze the sampling requirements imposed by the BDF and demonstrate their correctness by comparing the continuous BDFs of continuous test signals with their numerically approximated counterparts. Our results permit more accurate simulations using BDFs, which will be useful in applying them to problems such as partial coherence.

Optical phased arrays (OPAs) are crucial in beam-steering applications, particularly as transmitters in light detection and ranging and free-space communication systems. In this paper, we demonstrate a on-chip OPA that emits multiple orbital angular momentum (OAM) beams in different directions, each carrying unique topological charges. By superimposing a forked 1×3 Dammann grating on the grating array, six OAM beams with topological charges of ±3, ±4, and ±5 can be radiated from the OPA region. The OPA chip was fabricated on a silicon-on-insulator platform, and the simultaneous generation of multiple OAM beams was realized experimentally. The directions of these vortices can be steered by adjusting the wavelength of the input light and the bias voltages of the phase shifters, enabling a remarkable field of view (FOV) of 140 deg×40 deg within a 120-nm wavelength range. We pave the way for developing systems with ultrawide FOVs, improving the resolution of remote sensing and broadening the possibilities of free-space communications.