Publications by authors named "Hong-Bo Sun"

A plane blackbody serves as a standard radiation source, providing a precise quantitative relationship between input radiation and the output of infrared detectors, which is essential component of space infrared remote sensing instruments. However, current plane blackbodies fabricated by coating or surface structuring are unable to achieve uniform and stable high absorption in the ultrawide spectral range spanning the UV-VIS-NIR-MIR. Here, a femtosecond laser "V"- scanning method is proposed for the fabrication of cross-scale multi-layered micro- and nanocomposite structures on copper surfaces to realize ultrawide spectrum metallic plane blackbody with high absorption.

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Charge density wave (CDW) is the phenomenon of a material that undergoes a spontaneous lattice distortion and modulation of the electron density. Typically, the formation of CDW is attributed to Fermi surface nesting or electron-phonon coupling, where the CDW vector (Q) corresponds to localized extreme points of electronic susceptibility or imaginary phonon frequencies. Here, we propose a new family of multiple CDW orders, including chiral Star-of-David configuration in nine 2D III-VI van der Waals materials, backed by first-principles calculations.

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Article Synopsis
  • * The article highlights the benefits of combining these spin defects with 2D vdW materials and outlines challenges that remain, such as optimizing defect properties, spatial control, and integrating with photonic structures.
  • * Potential applications for this technology span various fields, including superconductivity, nanoelectronics, and biology, with a specific example being the use of quantum sensing for advanced DNA sequencing techniques.
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Atomic force microscope generally works by manipulating the absolute magnitude of the van der Waals force between tip and specimen. This force is, however, less sensitive to atom species than to tip-sample separations, making compositional identification difficult, even under multi-modal strategies or other atomic force microscopy variations. Here, we report the phenomenon of a light-modulated tip-sample van der Waals force whose magnitude is found to be material specific, which can be employed to discriminate heterogeneous compositions of materials.

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Article Synopsis
  • - The study introduces a unique organic molecule, BDVPN, known for its tunable photophysical properties and different structural forms (polymorphs).
  • - The BP phase of BDVPN has a "butterfly" shape with aligned wings, showing strong light-emission similar to dilute solutions, while the BN phase has an orthogonal wing conformation, leading to a different light-emission behavior.
  • - The BN phase exhibits impressive optical performance, featuring high efficiency, low-loss waveguides, deep-blue light amplification, and a significant color-changing response under pressure.
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The emitter-cavity strong coupling manifests crucial significance for exploiting quantum technology, especially in the scale of individual emitters. However, due to the small light-matter interaction cross-section, the single emitter-cavity strong coupling has been limited by its harsh requirement on the quality factor of the cavity and the local density of optical states. Herein, we present a strategy termed waveguide-assisted energy quantum transfer (WEQT) to improve the single emitter-cavity coupling strength by extending the interaction cross-section.

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Flexible multiplexing chips that permit reconfigurable multidimensional channel utilization are indispensable for revolutionary 6G terahertz communications, but the insufficient manipulation capability of terahertz waves prevents their practical implementation. Herein, we propose the first experimental demonstration of a flexible multiplexing chip for terahertz communication by revealing the unique mechanism of topological phase (TP) transition and perseveration in a heterogeneously coupled bilayer valley Hall topological photonic system. The synthetic and individual TPs operated in the coupled and decoupled states enable controllable on-chip modular TP transitions and subchannel switching.

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Crystallization is a fundamental phenomenon which describes how the atomic building blocks such as atoms and molecules are arranged into ordered or quasi-ordered structure and form solid-state materials. While numerous studies have focused on the nucleation behavior, the precise and spatiotemporal control of growth kinetics, which dictates the defect density, the micromorphology, as well as the properties of the grown materials, remains elusive so far. Herein, we propose an optical strategy, termed optofluidic crystallithography (OCL), to solve this fundamental problem.

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Invisibility, a fascinating ability of hiding objects within environments, has attracted broad interest for a long time. However, current invisibility technologies are still restricted to stationary environments and narrow band. Here, we experimentally demonstrate a Chimera metasurface for multiterrain invisibility by synthesizing the natural camouflage traits of various poikilotherms.

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Atomic and close-to-atom scale manufacturing is a promising avenue toward single-photon emitters, single-electron transistors, single-atom memory, and quantum-bit devices for future communication, computation, and sensing applications. Laser manufacturing is outstanding to this end for ease of beam manipulation, batch production, and no requirement for photomasks. It is, however, suffering from optical diffraction limits.

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Two-dimensional (2D) semiconductors, such as transition metal dichalcogenides, have emerged as important candidate materials for next-generation chip-scale optoelectronic devices with the development of large-scale production techniques, such as chemical vapor deposition (CVD). However, 2D materials need to be transferred to other target substrates after growth, during which various micro- and nanoscale defects, such as nanobubbles, are inevitably generated. These nanodefects not only influence the uniformity of 2D semiconductors but also may significantly alter the local optoelectronic properties of the composed devices.

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A novel high-sensitivity temperature sensor based on a chirped thin-core fiber Bragg grating Fabry-Perot interferometer (CTFBG-FPI) and the Vernier effect is proposed and demonstrated. With femtosecond laser direct writing technology, two CTFBG-FPIs with different interferometric cavity lengths are inscribed inside a thin-core fiber to form a Vernier effect system. The two FPIs consist of two pairs of CTFBGs with a full width at half maximum (FWHM) of 66.

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Article Synopsis
  • - Lithium niobate (LiNbO) is a promising material for nonlinear optics due to its strong nonlinear properties, but bulk crystals face challenges in achieving phase-matching for complex processes like high-harmonic generation (HHG).
  • - Researchers developed LiNbO metasurfaces that enhance light-matter interactions at the nanoscale, enabling efficient second-harmonic generation (SHG) and HHG, with demonstrated SHG efficiency of 5.1 × 10 cm GW and HHG reaching the 7th order with wavelengths as short as 226 nm.
  • - This advancement opens up possibilities for creating compact coherent white-light sources that can reach into the deep ultraviolet spectrum, which is valuable for various applications in
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Photonic topological states, providing light-manipulation approaches in robust manners, have attracted intense attention. Connecting photonic topological states with far-field degrees of freedom (d.o.

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High-resolution patterning of perovskite quantum dots (PQDs) is of significant importance for satisfying various practical applications, including high-resolution displays and image sensing. However, due to the limitation of the instability of PQDs, the existing patterning strategy always involves chemical reagent treatment or mask contact that is not suitable for PQDs. Therefore, it is still a challenge to fabricate high-resolution full-color PQD arrays.

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The design and actuation of soft robots are targeted at extreme motion control as well as high functionalization. In spite of robot construction optimized by bio-concepts, its motion system is still hindered by multiple actuator assembly and reprogrammable control for complex motions. Herein, our recent work is summarized and an all-light solution is proposed and demonstrated using graphene-oxide-based soft robots.

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Solid-state quantum emitters (QEs) are central components for photonic-based quantum information processing. Recently, bright QEs in III-nitride semiconductors, such as aluminum nitride (AlN), have attracted increasing interest because of the mature commercial application of the nitrides. However, the reported QEs in AlN suffer from broad phonon side bands (PSBs) and low Debye-Waller factors.

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Femtosecond lasers enable flexible and thermal-damage-free ablation of solid materials and are expected to play a critical role in high-precision cutting, drilling, and shaping of electronic chips, display panels, and industrial parts. Although the potential applications are theoretically predicted, true 3D nano-sculpturing of solids such as glasses and crystals, has not yet been demonstrated, owing to the technical challenge of negative cumulative effects of surface changes and debris accumulation on the delivery of laser pulses and subsequent material removal during direct-write ablation. Here, a femtosecond laser-induced cavitation-assisted true 3D nano-sculpturing technique based on the ingenious combination of cavitation dynamics and backside ablation is proposed to achieve stable clear-field point-by-point material removal in real time for precise 3D subtractive fabrication on various difficult-to-process materials.

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The implementation of transverse mode, polarization, frequency, and other degrees of freedom (d.o.f.

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Article Synopsis
  • Flexible perovskite solar cells (FPSCs) are promising for future electronics, but traditional transparent conductive electrodes like ITO lack flexibility.
  • The study introduces a new hybrid electrode made of silver nanowires and a flexible substrate, which combines high optical transmittance, electrical conductivity, and excellent mechanical flexibility.
  • The new electrode allows FPSCs to maintain 77.4% of their initial efficiency after 10,000 bending cycles, demonstrating its potential for durable, flexible solar energy solutions.
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Excitons are quasi-particles composed of electron-hole pairs through Coulomb interaction. Due to the atomic-thin thickness, they are tightly bound in monolayer transition metal dichalcogenides (TMDs) and dominate their optical properties. The capability to manipulate the excitonic behavior can significantly influence the photon emission or carrier transport performance of TMD-based devices.

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Electronic states are significantly correlated with chemical compositions, and the information related to these factors is especially crucial for the manipulation of the properties of matter. However, this key information is usually verified by after-validation methods, which could not be obtained during material processing, for example, in the field of femtosecond laser direct writing inside materials. Here, critical evolution stages of electronic states for monolayer tungsten diselenide (WSe) around the modification threshold (at a Mott density of ∼10 cm) are observed by broadband femtosecond transient absorption spectroscopy, which is associated with the intense femtosecond-laser-assisted oxygen-doping mechanism.

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Article Synopsis
  • Researchers are studying special materials called self-healing materials (SHMs) that can fix themselves, especially in electronics and robots.
  • They found a way to combine MXenes and graphene oxide (GO) to create devices that can heal from damage when exposed to moisture.
  • This new method has led to the creation of useful devices like sensors and generators that stay soft and can repair themselves, which could help make smaller and smarter electronics and robots in the future.
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