Topological surface states (TSSs) in a three-dimensional (3D) chiral woodpile photonic crystal (PhC) with layer displacement are experimentally investigated in the microwave regime. Both the original layered chiral PhC and the structure with an in-plane displacement of one of the periodic layers host Weyl points that give rise to TSSs. Microwave transmission measurements of the deformed chiral PhC show a clear edge localization of the TSSs, which is consistent with the numerical simulations. Further numerical calculations reveal that the frequencies and wavevectors of the Weyl points and the associated TSSs can be systematically tuned by the layer displacement. By scaling the 3D structure down to the nanoscale, the TSSs and their displacement-induced tunability can be extended to the near-infrared and visible optical regimes.
Harnessing the potential of a passively mode-locked, dual-section AlGaInAs/InP multiple quantum well (MQW) laser centered in the C-band, we generated a coherent optical frequency comb exhibiting a uniform 100 GHz channel spacing near 1550 nm. Remarkably, this source delivers exceptional spectral breadth: encompassing 52 discernible optical tones across a 40 nm bandwidth at the −20 dB level and extending to 100 tones spanning an impressive 80 nm bandwidth at −40 dB. To the best of our knowledge, this achievement establishes a new benchmark for spectral width among directly electrically pumped semiconductor mode-locked lasers based on quantum well active regions. Building upon this robust comb source, we further validated its practical utility by demonstrating successful data transmission at 25 Gbps per wavelength channel. These results collectively illuminate a promising pathway toward realizing terabit per second class ultra-high-capacity optical communication links utilizing integrated semiconductor comb technology.
Structured light denotes optical fields with engineered spatial degrees of freedom, including amplitude, phase, and polarization. It enables advanced functionalities in modern photonic systems and drives demands for compactness, stability, and multifunctionality. In this review, we provide a comprehensive overview of structured light generation and manipulation enabled by femtosecond laser 3D microfabrication. We outline representative 3D photonic structures for structured light generation and manipulation, including propagation-guided, single/multilayer-based, and continuous volumetric architectures. We summarize recent progress in 3D photonic devices, covering integrated emitters, compact beam generators, and intelligent photonic platforms, and discuss key challenges and future directions toward compact, stable, and multifunctional structured light systems.
To improve stability, we proposed a strategy of coating ZnO with CsPbBr3 quantum dots (QDs). The luminescence performance of CsPbBr3 QDs can be significantly enhanced by coating ZnO with CsPbBr3 QDs. Importantly, CsPbBr3-ZnO QDs exhibited higher stability under ultraviolet light and thermal conditions, retaining 67% and 72% of their photoluminescence (PL) intensity after seven cycles of heating and cooling and 7 h under 365-nm ultraviolet light. Time-resolved PL spectra revealed that the increase in the average lifetime of CsPbBr3-ZnO QDs mainly comes from the increase in radiative recombination and the decrease in non-radiative recombination (including surface state recombination and defect-level-related recombination). In addition, we fabricated green light-emitting diodes with CsPbBr3-ZnO QDs, which show great potential in the field of display screens.
