Advanced Photonics Research最新文献

Viologens, with their unique redox-active properties, have garnered increasing attention in the development of electrochromic devices. This review focuses on key strategies in molecular design, synthesis methodologies, and tailored functionalities that have propelled the field forward from 2019 to the present. The convergence of these approaches has led to the construction of viologen-based electrochromic materials with enhanced performance, stability, and responsiveness. The review not only examines the current state of the field but also explores promising outlooks and opportunities, including tailored applications, environmental sustainability, and integration with emerging technologies. The synergy between molecular engineering and viologen-based electrochromic materials holds significant promise, shaping the future of dynamic, responsive materials in diverse technological domains. This review serves as a valuable resource for researchers, offering insights into recent breakthroughs and inspiring further advancements in this rapidly evolving field.

Diffractive Neural Networks

In article number 2300310, Ying Zhi Cheong, Blanca del Rosal, Sharath Sriram, and co-workers propose and demonstrate a microscale multi-layer diffractive neural network approach that classifies various wavelengths in the visible spectrum. This miniaturised classification approach, achieved through two-photon polymerization, has potential application in medical diagnosis to material science, enabling rapid detection of analytes based on the presence of optical extinction bands at specific wavelengths.

Perovskites exhibit appealing optical and electrical properties, making them attractive candidates for efficient luminescent materials with low-cost and straightforward fabrication processes. Their versatility is highlighted by the ability to deposit perovskite thin films on various substrates, including silicon, glass, sapphire, and flexible substrates, enabling potential monolithic integration on silicon for applications such as photonic integrated circuits, high-speed communication. Extensive studies on perovskite light-emitting diodes have shown external quantum efficiencies exceeding 20% across a wide spectral range from deep blue to near-infrared, with chirality. Additionally, perovskite-based lasing action has been achieved under pulsed optical excitation and continuous-wave operation, as well as in functional diode structures. However, realizing electrically driven perovskite laser diodes for practical applications requires the injection of intense current densities. This review provides a comprehensive overview of the historical progress in perovskite lasers and light-emitting didoes, along with important design considerations essential for their development.

Herein, lutecium silicate is used as a rock example to investigate its two high-pressure phases (7.4 GPa: HP-II and 25.3 GPa: HP-III) and lattice dynamics by in situ high-pressure Raman scattering up to 35.1 GPa. The evidence for a highly symmetrical insulator HP-III phase is obtained. Importantly, the high-pressure structure (metastable phases) after pressure quenching is also intercepted, indicating pressure-induced permanent densification. These findings provide Raman evidence for pressure-induced successive phase transitions of highly symmetric insulators intercepted in prototype Lu₂SiO₅ and physical insights to explain the self-regulation of rare earth-rich regions in facilitating highly effective global carbon cycling.

The high-temperature layered superconductor (HTS) BSCCO is one of the key quantum material platforms in THz science and technology. Compact, stable, and reliable BSCCO THz photonic integrated circuit components can be developed to effectively and efficiently control and manipulate THz wave radiation, especially for future communication systems and network applications. Herein, the design, simulation, and modeling of ultrafast THz metamaterial photonic integrated circuits are reported on a few nanometer-thick HTS BSCCO van der Waals (vdWs), capable of the active modulation of phase with constant transmission coefficient over a narrow-frequency range. Meanwhile, the metamaterial circuit works as an amplitude modulator without significantly changing the phase in a different frequency band. Under the application of ultrashort optical pulses, the transient modulation dynamics of the THz metamaterial offer a fast-switching timescale of 50 ps. The dynamics of picosecond light–matter interaction, Cooper pairs breaking, photoinduced quasiparticles generation and recombination, phonon bottleneck effect, and emission and relaxation of bosons in BSCCO vdW metamaterial arrays are discussed for the potential application of multifunctional superconducting photonic integrated circuits in communication and quantum technologies.

Mode-locked lasers are prone to exhibit a wide range of dynamics, including the coherent dissipative soliton with high robustness or the possible emission of incoherent pulse bursts. Herein, it is proposed to expand the notion of dissipative breathing solitons to incoherent localized formation, which is illustrated experimentally by reporting original coherent and incoherent breathing solitons generated in a 2 μm bidirectional ultrafast fiber laser. A real-time spectral characterization of the breathing soliton dynamics with different coherence is provided, highlighting salient features of the self-organization. The switching between coherent breathing soliton and noise-like pulse is also experimentally demonstrated, corresponding to the multiple transient decoherence and coherence recovery. High behavior similarity exists in bidirectional solitons evolution owing to the common gain and loss modulation. Numerical simulations using a discrete laser model validate the experimental findings. This research generalizes previous observations of breathing solitons made in the coherent case and opens up new possibilities for generating breathers in various dissipative systems.

Although orbital angular momentum (OAM) is extensively explored and researched in various scientific domains, its practical application in wireless communications still faces numerous challenges. Notably, existing OAM beam generation technologies need to meet the diversified demands of modern wireless communication, such as miniaturization, cost-effectiveness, and system integration. Driven by the immense potential of OAM in communication systems, in this work, an innovative method based on leaky cables capable of simultaneously generating multiple vortex beams, overcoming a series of implementation issues associated with multiplexing emitters, is introduced. A design prototype is fabricated and tested, and the measurement results align closely with the simulations, validating the multifunctionality and practicality of the method. Moreover, the proposed strategy can seamlessly extend to optical frequencies using the concept of leaky fibers. In this method, not only efficient spatial utilization and excellent isolation are realized but also high cost-effectiveness is possessed. Compared to previous strategies, this technique may have an impact on simplifying the establishment of communication system platforms based on OAM multiplexing.

Coupled microring lattices are versatile photonic systems that can be used to realize various topological phases of matter. In two-dimensional (2D) microring lattices, the periodic and unidirectional circulation of light in each microring gives rise to a time-like dimension, so that the lattice emulates a (2 + 1)D system with much richer topological behaviors than static 2D lattices. Accurate treatment of these systems requires a departure from the static tight-binding model of coupled resonators and take into account the periodic coupling sequence of light in the lattice network. This article provides an overview of the theory and design of (2 + 1)D microring lattices for realizing Floquet topological photonic insulators (TPIs). Particular focus is placed on the microring Lieb lattice with perfect couplings, which emulates an anomalous Floquet insulator with all flat bands. Such a system exhibits some unique properties, including wide edge mode continuum exceeding a Floquet–Brillouin zone, super-robustness to lattice disorder, Aharonov–Bohm (AB) caging and compact localized flat-band states that can be used to realize high-quality factor topological resonators. All-bands-flat Floquet–Lieb microring lattices provide a versatile platform for investigating topological physics as well as potential applications in realizing topologically-protected photonic devices.

Miura origami's reconfigurable characteristic and structural asymmetry, combined with electromagnetic (EM) wave manipulation, crashed a unique spark. However, the complexity of the three-dimensional (3D) origami structure after folding makes it challenging to study the phase regulation mechanism. Here, we propose a reconfigurable phase gradient metasurface based on Miura origami and derive the underlying mechanism of phase modulation in detail under linearly and circularly polarized (LP and CP) incidence. We adopt the one-dimensional (1D) gradient design along the x direction to verify the idea. The phase calculation formulas are given under LP and CP incidence through the Jones matrix's derivation. The beam deflector angles corresponding to LP and CP waves are identical in the planar state. As the folding angle increases, the phase evolution rules corresponding to the LP and CP waves are discrepant, leading to differential beam steering. Finally, the origami sample is processed for verification, and the experimental data are consistent with the simulation and theoretically calculated values. We believe this work can help analyze the EM behavior of complex 3D origami structures and lay a foundation for designing a multifunctional EM origami metasurface.

Symmetry-protected bound states in the continuum (BICs), emerging at the $��{\Gamma }_0�$ point in the Brillouin zone of periodic lattices of scatters, are robust optical modes under modifications in the lattice if the C₂ symmetry (two fold rotational symmetry) is preserved. In this study, the manipulation of these symmetry-protected BIC and quasi-BIC modes in a system comprising two metallic rods per unit cell by adjusting their lateral separation and displacement is focused on. With non-symmetric systems under 180° rotation, two distinct coupling mechanisms resulting from changes in the lateral separation are investigated: the coupling of two half-wavelength (λ/2) resonances and the coupling of two surface lattice resonances (SLRs). Notably, symmetric structures with minimal lateral separation cannot sustain BIC modes owing to the near-field coupling between the rods. However, when the lateral separation is sufficiently large, the existence of a BIC mode supported by an SLR remains robust even with positional shifts. Furthermore, increasing the lateral separation and the shift displacement between the rods in asymmetric systems induces a redshift and a blueshift in the quasi-BIC mode, respectively. This shift is attributed to the near-field coupling effect between two rods, enabling the tunability of the resonance frequency with a high-quality factor.