Search

The ability to draw a structured surface plasmon polariton (SPP) field is an important step toward many new opportunities for a broad range of nanophotonic applications. Previous methods usually require complex experimental systems or holographic optimization algorithms that limit their practical applications. Here, we propose a simple method for flexible generation of structured SPP field with on-chip plasmonic metalenses. The metalens is composed of multiple plasmonic focusing nanostructures whose focal shape and position can be independently manipulated, and through their superposition, SPP fields with specially designed patterns are obtained. Based on this method, we demonstrate several structured SPP fields including S- and W-shaped SPP focal fields and tunable SPP bottle beams. This work could provide new ideas for on-chip manipulation of optical surface waves, and contribute to applications such as on-chip photonic information processing and integrated photonic circuits.

Twisted two-dimensional bilayer materials exhibit many exotic electronic phenomena. Manipulating the 'twist angle' between the two layers enables fine control of the electronic band structure, resulting in magic-angle flat-band superconductivity.sup.1,2, the formation of moiré excitons.sup.3-8 and interlayer magnetism.sup.9. However, there are limited demonstrations of such concepts for photons. Here we show how analogous principles, combined with extreme anisotropy, enable control and manipulation of the photonic dispersion of phonon polaritons in van der Waals bilayers. We experimentally observe tunable topological transitions from open (hyperbolic) to closed (elliptical) dispersion contours in bilayers of [alpha]-phase molybdenum trioxide ([alpha]-MoO.sub.3), arising when the rotation between the layers is at a photonic magic twist angle. These transitions are induced by polariton hybridization and are controlled by a topological quantity. At the transitions the bilayer dispersion flattens, exhibiting low-loss tunable polariton canalization and diffractionless propagation with a resolution of less than [lambda].sub.0/40, where [lambda].sub.0 is the free-space wavelength. Our findings extend twistronics.sup.10 and moiré physics to nanophotonics and polaritonics, with potential applications in nanoimaging, nanoscale light propagation, energy transfer and quantum physics. The photonic dispersion of phonon polaritons in bilayers of [alpha]-phase molybdenum trioxide can undergo tunable topological transitions at magic interlayer twist angles., Author(s): Guangwei Hu [sup.1] [sup.2] , Qingdong Ou [sup.3] , Guangyuan Si [sup.4] , Yingjie Wu [sup.3] , Jing Wu [sup.5] , Zhigao Dai [sup.3] [sup.6] , Alex Krasnok [sup.2] [...]

The excellent optoelectronic properties and structural stability of inorganic cesium lead halide perovskites make them promising candidates for multiple types of optoelectronic devices. However, it remains a challenge to fabricate monocrystalline phase‐pure perovskite microstructures by facile low‐temperature solution‐based methods. Herein, a solution‐based method is demonstrated for controlling the crystallization of cesium halide perovskite microstructures. The structure of perovskite crystals is successfully tuned from non‐corner sharing Cs4PbBr6 (0D) to corner‐sharing CsPbBr3 (3D) to layered CsPb2Br5 (2D) by controlling water (H2O) to dimethylsulfoxide (DMSO) ratios. Molecular dynamics simulations and thermodynamic analysis indicate that the relative stability of Pb2+ and Br− ions in solution is the key factor in determining which crystals form at different H2O/DMSO ratios, with Cs+ simply incorporated as needed. The phase‐pure 0D crystals exhibit a high photoluminescence quantum yield of 41%, whilst the 2D crystals have an onset of absorption at 350 nm. Furthermore, the as‐synthesized, highly uniform 3D perovskite single crystals are coupled with nanofabricated interdigitated electrodes to show excellent X‐ray detection, with a high sensitivity of 8000 μC Gyair−1cm−2 obtained under a 0.5V external bias. This is comparable to many commercial X‐ray detectors (Si, α‐Se) and several times higher than other reported inorganic perovskite materials (CsPbBr3 quantum dots, Cs2AgBiBr6). [ABSTRACT FROM AUTHOR]

Keywords: bottle beams; plasmonic metalens; surface plasmon polariton EN bottle beams plasmonic metalens surface plasmon polariton 1969 1976 8 05/12/22 20220401 NES 220401 1 Introduction Surface plasmon polariton (SPP), with the capability of breaking through the traditional optical diffraction limit [[1], [2]], shows advantages of nanoscale spatial resolution and tremendous localized electromagnetic field enhancement [[3]]. DIAGRAM: Figure 3: Generation of SPP bottle beam by proposed metalens.(a) Schematic diagram of the principle of synthesizing SPP bottle beam. Based on this principle, we designed and generated a series of SPP fields, including S- and W-shaped SPP focal fields and SPP bottle beams, and the effectiveness of the proposed method is verified experimentally. [Extracted from the article]