Optical metasurfaces have emerged as a groundbreaking technology in photonics, offering unparalleled control over light–matter interactions at the subwave

Optical metasurfaces have emerged as a groundbreaking technology in photonics, offering unparalleled control over light–matter interactions at the subwavelength scale with ultrathin surface nanostructures and thereby giving birth to flat optics. While most reported optical metasurfaces are static, featuring well-defined optical responses determined by their compositions and configurations set during fabrication, dynamic optical metasurfaces with reconfigurable functionalities by applying thermal, electrical, or optical stimuli have become increasingly more in demand and moved to the forefront of research and development. Among various types of dynamically controlled metasurfaces, electrically tunable optical metasurfaces have shown great promise due to their fast response time, low power consumption, and compatibility with existing electronic control systems, offering unique possibilities for dynamic tunability of light–matter interactions via electrical modulation. Here we provide a comprehensive overview of the state-of-the-art design methodologies and technologies explored in this rapidly evolving field. Our work delves into the fundamental principles of electrical modulation, various materials and mechanisms enabling tunability, and representative applications for active light-field manipulation, including optical amplitude and phase modulators, tunable polarization optics and wavelength filters, and dynamic wave-shaping optics, including holograms and displays. The review terminates with our perspectives on the future development of electrically triggered optical metasurfaces.show less

An ultrasonic phase extraction method is proposed for co-cable identification without modifying transceivers in coherent optical transmission systems. To

An ultrasonic phase extraction method is proposed for co-cable identification without modifying transceivers in coherent optical transmission systems. To extract the ultrasonic phase, we apply an improved residual frequency offset compensation algorithm, an optimized unwrapping algorithm for mitigating phase noise induced by phase ambiguity between digital signal processing (DSP) blocks, and an averaging operation for improving the phase sensitivity. In a 64-GBaud dual-polarization quadrature phase shift keying (DP-QPSK) simulation system, the phase sensitivity of the proposed method reaches 0.03 rad using lasers with 100-kHz linewidth and a 60-kHz ultrasonic source, with only 400 k-points (kpts) stored data. Also verified by an experiment under the same transmission conditions, the sensitivity reaches 0.39 rad, with 3 kpts of data stored and no averaging due to the equipment limitation. The results have shown this method provides a better choice for low-cost and real-time co-cable identification in integrated sensing and communication optical networks.show less

The orbital angular momentum (OAM) of photons provides a pivotal resource for carrying out high-dimensional classical and quantum information processing d

The orbital angular momentum (OAM) of photons provides a pivotal resource for carrying out high-dimensional classical and quantum information processing due to its unique discrete high-dimensional nature. The cyclic transformation of a set of orthogonal OAM modes is an essential building block for universal high-dimensional information processing. Its realization in the quantum domain is the universal quantum Pauli-X gate. In this work, we experimentally demonstrate a cyclic transformation of six OAM modes with an averaged efficiency higher than 96% by exploiting a nonreciprocal Mach–Zehnder interferometer. Our system is simple and can, in principle, be scaled to more modes. By improving phase stabilization and inputting quantum photonic states, this method can perform universal single-photon quantum Pauli-X gate, thus paving the way for scalable high-dimensional quantum computation.show less

Nondeterministic-polynomial-time (NP)-complete problems are widely involved in various real-life scenarios but are still intractable in being solved effic

Nondeterministic-polynomial-time (NP)-complete problems are widely involved in various real-life scenarios but are still intractable in being solved efficiently on conventional computers. It is of great practical significance to construct versatile computing architectures that solve NP-complete problems with computational advantage. Here, we present a reconfigurable integrated photonic processor to efficiently solve a benchmark NP-complete problem, the subset sum problem. We show that in the case of successive primes, the photonic processor has genuinely surpassed electronic processors launched recently by taking advantage of the high propagation speed and vast parallelism of photons and state-of-the-art integrated photonic technology. Moreover, we are able to program the photonic processor to tackle different problem instances, relying on the tunable integrated modules, variable split junctions, which can be used to build a fully reconfigurable architecture potentially allowing 2N configurations at most. Our experiments confirm the potential of the photonic processor as a versatile and efficient computing platform, suggesting a possible practical route to solving computationally hard problems at a large scale.show less