Hyperbolic media have attracted much attention in the photonics community due to their ability confine light arbitrarily small volumes and potential applications super-resolution technologies. The two-dimensional counterparts of these can be achieved with hyperbolic metasurfaces that support in-plane guided modes upon nanopatterning, which, however, poses notable fabrication challenges limits achievable confinement. We show thin flakes a van der Waals crystal, α-MoO3, naturally polariton at...

Controlling the twist angle between two stacked van der Waals (vdW) crystals is a powerful approach for tuning their electronic and photonic properties. Hyperbolic media have recently attracted much attention due to ability tailor electromagnetic waves at subwavelength-scale which, however, usually requires complex patterning procedures. Here, we demonstrate lithography-free manipulating hyperbolicity by harnessing twist-dependent coupling of phonon polaritons in double-layers vdW α-MoO3,...

Abstract One of the main bottlenecks in development terahertz (THz) and long-wave infrared (LWIR) technologies is limited intrinsic response traditional materials. Hyperbolic phonon polaritons (HPhPs) van der Waals semiconductors couple strongly with THz LWIR radiation. However, mismatch photon − polariton momentum makes far-field excitation HPhPs challenging. Here, we propose an In-Plane Polariton Tuner that based on patterning semiconductors, here α-MoO 3 , into ribbon arrays. We...

Hyperbolic phonon polaritons (HPhPs) sustained in polar van der Waals (vdW) crystals exhibit extraordinary confinement of long-wave electromagnetic fields to the deep subwavelength scale. In stark contrast uniaxial vdW hyperbolic materials, recently emerged biaxial such as α-MoO3 and α-V2 O5 , offer new degrees freedom for controlling light two-dimensions due their distinctive in-plane dispersions. However, control focusing these HPhPs remain elusive. Here, a versatile technique is proposed...

An analytical waveguide model is developed to describe the polaritons in two-dimensional van der Waals crystals.

Abstract Polar van der Waals (vdW) crystals that support phonon polaritons have recently attracted much attention because they can confine infrared and terahertz (THz) light to deeply subwavelength dimensions, allowing for the guiding manipulation of at nanoscale. The practical applications these in devices rely strongly on deterministic engineering their spatially localized electromagnetic field distributions, which has remained challenging. polariton interference be enhanced tailored by...

Specific geometric morphology and improved crystalline properties are of great significance for the development materials in micro-nano scale. However, high-melting molybdenum (Mo), it is difficult to get high-quality structures exhibiting a single-crystalline nature preconceived simultaneously. In this paper, pyramid-shaped Mo nanostructure was prepared through thermal evaporation technique, as well series experimental controls. Based on detailed characterizations, growth mechanism...

Abstract Highly confined and low‐loss hyperbolic phonon polaritons (HPhPs) sustained in van der Waals crystals exhibit outstanding potential to concentrate the long‐wave electromagnetic fields deep into subwavelength region. However, precise tuning on HPhP propagation characteristics is a critical challenge facilitate its practical applications nanophotonic devices circuits. This study, by taking advantage of varying air gaps suspended α‐MoO 3 crystal, shows feasibility tune wavelength...

Hyperbolic Phonon Polaritons Launching, controlling, and focusing of in-plane hyperbolic phonon polaritons in van der Waals α-MoO3 with geometrically designed curved gold plasmonic antennas are realized by Huanjun Chen, Shaozhi Deng, co-workers article number 2104164. By engineering the curvature antenna extremity, it is possible to tune focal lengths lateral sizes points. This study can open up new avenues for planar nanophotonic devices mid-infrared region.

Néel-type optical target skyrmions arise from transverse-magnetic-polarized evanescent electromagnetic fields with rotational symmetry. Supported on a graphene monolayer disk, these nanoscale exhibit diameters of 100 nm.

The enhancement of electron-phonon interaction provides a reasonable explanation for gate-tunable phonon properties in some semiconductors where multiple inequivalent valleys are simultaneously occupied upon charge doping, especially few-layer transition metal dichalcogenides (TMDs). In this work, we report var der Waals epitaxy 2H-MoSe2 by molecular beam (MBE) and monolayer bilayer MoSe2. MoSe2, find that out-of-plane mode A1g exhibits strong softening shifting toward lower wavenumbers at...

In article number 2004872, Huanjun Chen, Shaozhi Deng, and co-workers realize a nanoscale tailoring of mid-infrared electromagnetic field localizations in van der Waals α-MoO3 microstructures different shapes sizes. This is enabled by the synergy in-plane hyperbolic phonon polaritons spatial confinement effects. Furthermore, authors show that orientation isofrequency curve relative to microstructure edge critical parameter governing localized distributions.

Laser conditioning is an effective method to improve the laser damage threshold of HfO2/SiO2 multilayer films prepared by electron beam evaporation. In this paper, some parameters that can affect efficiency were discussed. The result maximum fluence should be less than 90% its unconditioned induced (LIDT) avoid film. increment between pulses and steps has a great influence on improvement high reflective coatings. coverage light intensity defect as wide possible, irradiation possible. main...

Abstract Development of terahertz (THz) and long-wave infrared (LWIR) technologies is mainly bottlenecked by the limited intrinsic response traditional materials. Hyperbolic phonon polaritons (HPhPs) van der Waals semiconductors couple strongly with THz LWIR radiation. However, mismatch photon−polariton momentum makes far-field excitation HPhPs challenging. Here, we propose an In-Plane Polariton Tuner demonstrate a first device responding to direct giving rise unique set characteristic...

A series of (SrNa)2-xEux(MoO4)3 red phosphors have been synthesized by using the sol-gel method. X-ray diffraction, used to characterize crystallization process phosphor precursors, indicates that had an SrMoO4 structure. The properties these resulting also characterized photoluminescence (PL) spectra. PL results indicate all exhibit intense emissions under 275, 395, and 465-nm excitation. two strongest lines at 395 465 nm in excitation spectra match well with popular from near-UV blue...

Hyperbolic media have attracted much attention in the photonics community, thanks to their ability confine light arbitrarily small volumes and use for super-resolution applications. The 2D counterpart of these can be achieved with hyperbolic metasurfaces, which support in-plane guided modes nanopatterns which, however, pose significant fabrication challenges limit achievable confinement. We show that thin flakes van der Waals material {\alpha}-MoO3 naturally polariton at mid-infrared...

Development of terahertz (THz) and long-wave infrared (LWIR) technologies is mainly bottlenecked by the limited intrinsic response traditional materials. Hyperbolic phonon polaritons (HPhPs) van der Waals semiconductors couple strongly with THz LWIR radiation. However, mismatch photon-polariton momentum makes far-field excitation HPhPs challenging. Here, we propose an In-Plane Polariton Tuner that based on patterning semiconductors, here α-MoO3, into ribbon arrays. We demonstrate such tuners...

Optical skyrmions, the optical analogue of topological configurations formed by three-dimensional vector fields covering whole 4{\pi} solid angle but confined in a two-dimensional (2D) domain, have recently attracted growing interest due to their potential applications high-density data transfer, storage, and processing. While skyrmions been successfully demonstrated using different field vectors both free-space propagating near-field evanescent electromagnetic fields, study on generation...

Two-dimensional van der Waals (vdW) crystals can sustain various types of polaritons with strong electromagnetic confinements, making them highly attractive for the nanoscale photonic and optoelectronic applications. While extensive experimental numerical studies are devoted to vdW crystals, analytical models sparse. Particularly, applying such a model describe polariton behaviors visualized by state-of-art near-field optical microscopy requires further investigation. Herein, we develop an...

Polar van der Waals (vdW) crystals that support phonon polaritons have recently attracted much attention because they can confine infrared and terahertz (THz) light to deeply subwavelength dimensions, allowing for the guiding manipulation of at nanoscale. The practical applications these in devices rely strongly on deterministic engineering their spatially localized electromagnetic field distributions, which has remained challenging. This study demonstrates polariton interference be enhanced...