arXiv subjects

Xiaoyang Duan

Publications and source records attributed to Xiaoyang Duan.

At least 19 recordsLinked to original sources

arXiv2026

An Improvement-Path Framework and an Exact Algorithm for Single-Machine Scheduling with Release Times

This paper studies the non-preemptive single-machine scheduling problem with heterogeneous release times and processing times, with the objective of minimizing total waiting time. The problem is known to be NP-hard. By modeling machine idle time as negative waiting time, we establish a unified waiting-time formulation that compresses the original four-dimensional description into a two-dimensional representation depending only on processing times and waiting times, thereby substantially simplifying the structural analysis of the problem. Based on this representation, ideal directions are defined from the structure induced by an optimal solution, and it is shown that every non-optimal schedule admits an ideal improvement path. It is further proved that improvable ideal directions require no coordination and can therefore be treated as independent improvement units. The theoretical analysis also shows that the realizability of every improvable ideal direction can be determined in finitely many steps, thereby laying the foundation for an overall solution framework. For each improvable ideal direction, by analyzing the propagation of the decrease flow and the increase flow under local adjustments, we prove that queue discontinuity is the unique structural obstacle to the realization of ideal improvement paths. A complete characterization of the resulting local optima is then established, and corresponding repair operators are designed. On this basis, an iterative repair algorithm under the improvement-path framework is developed. It is proved to terminate in finitely many steps, return a globally optimal schedule, and admit an explicit upper bound on its time complexity. This work provides a new analytical perspective and solution framework for this class of NP-hard scheduling problems.

math.GM↗

arXiv2025

Transformable Plasmonic Helix with Swinging Gold Nanoparticles

Control over multiple optical elements that can be dynamically rearranged to yield substantial three-dimensional structural transformations is of great importance to realize reconfigurable plasmonic nanoarchitectures with sensitive and distinct optical feedback. In this work, we demonstrate a transformable plasmonic helix system, in which multiple gold nanoparticles (AuNPs) can be directly transported by DNA swingarms to target positions without undergoing consecutive stepwise movements. The swingarms allow for programmable AuNP translocations in large leaps within plasmonic nanoarchitectures, giving rise to tailored circular dichroism spectra. Our work provides an instructive bottom-up solution to building complex dynamic plasmonic systems, which can exhibit prominent optical responses through cooperative rearrangements of the constituent optical elements with high fidelity and programmability.

physics.bio-ph↗

arXiv2024

Nearfield Vortex Dynamics of Supercell Bloch Modes

Densely arranged optical vortices are natural solutions of high-symmetry Bloch modes in photonic crystals. However, strict symmetry constraints limit the potential spatial configurations of nearfield vortices, restricting the control over light-matter interaction. Here, we demonstrate a nearfield vortex dynamic within a supercell photonic crystal. By introducing paired rotations of triangular structures, we achieve high-quality-factor Bloch mode transition from evanescent valley modes, to quasi-bound states in the continuum, frustrated modes, and quasi-valleys. Each stage exhibits distinct nearfield vortex distributions, nonlinear overlap properties, and quality factors, revealing diverse physical behaviors for tailoring light-matter interaction. Notably, the asymmetric vortex configuration of frustrated modes enhances second harmonic generation, driven by an optimized nonlinear overlap factor. Our paired-rotation strategy offers a versatile design framework for creating supercell photonic crystals with unique nearfield vortex properties, presenting promising applications in lasing, nonlinear optics and optical forces.

physics.optics↗

arXiv2021

A light-driven three-dimensional plasmonic nanosystem that translates molecular motion into reversible chiroptical function

Nature has developed striking light-powered proteins such as bacteriorhodopsin, which can convert light energy into conformational changes for biological functions. Such natural machines are a great source of inspiration for creation of their synthetic analogues. However, synthetic molecular machines typically operate at the nanometre scale or below. Translating controlled operation of individual molecular machines to a larger dimension, for example, to 10-100 nm, which features many practical applications, is highly important but remains challenging. Here we demonstrate a light-driven plasmonic nanosystem that can amplify the molecular motion of azobenzene through the host nanostructure and consequently translate it into reversible chiroptical function with large amplitude modulation. Light is exploited as both energy source and information probe. Our plasmonic nanosystem bears unique features of optical addressability, reversibility and modulability, which are crucial for developing all-optical molecular devices with desired functionalities.

physics.optics↗

arXiv2021

Dynamic plasmonic color generation enabled by functional materials

Displays are an indispensable medium to visually convey information in our daily life. Although conventional dye-based color displays have been rigorously advanced by world leading companies, critical issues still remain. For instance, color fading and wavelength-limited resolution restrict further developments. Plasmonic colors emerging from resonant interactions between light and metallic nanostructures can overcome these restrictions. With dynamic characteristics enabled by functional materials, dynamic plasmonic coloration may find a variety of applications in display technologies. In this review, we elucidate basic concepts for dynamic plasmonic color generation and highlight recent advances. In particular, we devote our review to a selection of dynamic controls endowed by functional materials, including magnesium, liquid crystals, electrochromic polymers, and phase change materials. We also discuss their performance in view of potential applications in current display technologies.

physics.optics↗

arXiv2021

Dynamic plasmonic colour display

Plasmonic colour printing based on engineered metasurfaces has revolutionized colour display science due to its unprecedented subwavelength resolution and high-density optical data storage. However, advanced plasmonic displays with novel functionalities including dynamic multicolour printing, animations, and highly secure encryption have remained in their infancy. Here we demonstrate a dynamic plasmonic colour display technique that enables all the aforementioned functionalities using catalytic magnesium metasurfaces. Controlled hydrogenation and dehydrogenation of the constituent magnesium nanoparticles, which serve as dynamic pixels, allow for plasmonic colour printing, tuning, erasing and restoration of colour. Different dynamic pixels feature distinct colour transformation kinetics, enabling plasmonic animations. Through smart material processing, information encoded on selected pixels, which are indiscernible to both optical and scanning electron microscopies, can only be read out using hydrogen as a decoding key, suggesting a new generation of information encryption and anti-counterfeiting applications.

physics.optics↗

arXiv2021

A plasmonic nanorod that walks on DNA origami

In nano-optics, a formidable challenge remains in precise transport of a single optical nano-object along a programmed and routed path toward a predefined destination. Molecular motors in living cells that can walk directionally along microtubules have been the inspiration for realizing artificial molecular walkers. Here we demonstrate an active plasmonic system, in which a plasmonic nanorod can execute directional, progressive and reverse nanoscale walking on two or three-dimensional DNA origami.Such a walker comprises an anisotropic gold nanorod as its body and discrete DNA strands as its feet. Specifically, our walker carries optical information and can in situ optically report its own walking directions and consecutive steps at nanometer accuracy, through dynamic coupling to a plasmonic stator immobilized along its walking track. Our concept will enable a variety of smart nanophotonic platforms for studying dynamic light-matter interaction, which requires controlled motion at the nanoscale well below the optical diffraction limit.

physics.bio-ph↗

arXiv2021

Chiral plasmonics

We present a comprehensive overview of chirality and its optical manifestation in plasmonic nanosystems and nanostructures. We discuss top-down fabricated structures that range from solid metallic nanostructures to groupings of metallic nanoparticles arranged in three dimensions. We also present the large variety of bottom-up synthesized structures. Using DNA, peptides, or other scaffolds, complex nanoparticle arrangements of up to hundreds of individual nanoparticles have been realized. Beyond this static picture, we also give an overview of recent demonstrations of active chiral plasmonic systems, where the chiral optical response can be controlled by an external stimulus. We discuss the prospect of using the unique properties of complex chiral plasmonic systems for enantiomeric sensing schemes.

physics.optics↗

arXiv2021

A rotary plasmonic nanoclock

One of the fundamental challenges in nanophotonics is to gain full control over nanoscale optical elements. The precise spatiotemporal arrangement determines their interactions and collective behavior. To this end, DNA nanotechnology is employed as an unprecedented tool to create nanophotonic devices with excellent spatial addressability and temporal programmability. However, most of the current DNA-assembled nanophotonic devices can only reconfigure among random or very few defined states. Here, we demonstrate a DNA-assembled rotary plasmonic nanoclock. In this system, a rotor gold nanorod can carry out directional and reversible 360 degree rotation with respect to a stator gold nanorod, transitioning among 16 well-defined configurations powered by DNA fuels. The full-turn rotation process is monitored by optical spectroscopy in real time. We further demonstrate autonomous rotation of the plasmonic nanoclock powered by DNAzyme-RNA interactions. Such assembly approaches pave a viable route towards advanced nanophotonic systems entirely from the bottom-up.

physics.app-ph↗

arXiv2021

Stabilizing $γ$-MgH$_2$ at Nanotwins in Mechanically Constrained Nanoparticles

Reversible hydrogen uptake and the metal/dielectric transition make the Mg/MgH$_2$ system a prime candidate for solid state hydrogen storage and dynamic plasmonics. However, high dehydrogenation temperatures and slow dehydrogenation hamper broad applicability. One promising strategy to improve dehydrogenation is the formation of metastable $γ$-MgH$_2$. A nanoparticle (NP) design, where $γ$-MgH$_2$ forms intrinsically during hydrogenation is presented and a formation mechanism based on transmission electron microscopy results is proposed.Volume expansion during hydrogenation causes compressive stress within the confined, anisotropic NPs, leading to plastic deformation of $β$-MgH$_2$ via (301) $β$ twinning. It is proposed that these twins nucleate $γ$-MgH$_2$ nanolamellas, which are stabilized by residual compressive stress. Understanding this mechanism is a crucial step toward cycle-stable, Mg-based dynamic plasmonic and hydrogen-storage materials with improved dehydrogenation. It is envisioned that a more general design of confined NPs utilizes the inherent volume expansion to reform $γ$-MgH$_2$ during each rehydrogenation

cond-mat.mtrl-sci↗

arXiv2021

Magnesium for Dynamic Nanoplasmonics

The key component of nanoplasmonics is metals. For a long time, gold and silver have been the metals of choice for constructing plasmonic nanodevices because of their excellent optical properties. However, these metals possess a common characteristic, i.e., their optical responses are static. The past decade has been witnessed tremendous interest in dynamic control of the optical properties of plasmonic nanostructures. To enable dynamic functionality, several approaches have been proposed and implemented. For instance, plasmonic nanostructures can be fabricated on stretchable substrates or on programmable templates so that the interactions between the constituent metal nanoparticles and therefore the optical responses of the plasmonic systems can be dynamically changed. Also, plasmonic nanostructures can be embedded in tunable dielectric materials, taking advantage of the sensitive dependence of the localized surface plasmon resonances on the neighboring environment. Another approach, which is probably the most intriguing one, is to directly regulate the carrier densities and dielectric functions of the metals themselves.

physics.optics↗

arXiv2021

Dynamic Plasmonic System That Responds to Thermal and Aptamer-Target Regulations

The DNA origami technique has empowered a new paradigm in plasmonics for manipulating light and matter at the nanoscale. This interdisciplinary field has witnessed vigorous growth, outlining a viable route to construct advanced plasmonic architectures with tailored optical properties. However, so far plasmonic systems templated by DNA origami have been restricted to respond to only single stimuli. Despite broad interest and scientific importance, thermal and aptamer-target regulations have not yet been widely utilized to reconfigure three-dimensional plasmonic architectures. In this Letter, we demonstrate a chiral plasmonic nanosystem integrated with split aptamers, which can respond to both thermal and aptamer-target regulations. We show that our dual-responsive system can be noninvasively tuned in a wide range of temperatures, readily correlating thermal control with optical signal changes. Meanwhile, our system can detect specific targets including adenosine triphosphate and cocaine molecules, which further enhance the optical response modulations and in turn influence the thermal tunability.

physics.app-ph↗

arXiv2021

Scanning Plasmonic Color Display

Control over plasmonic colors on the nanoscale is of great interest for high-resolution display, imaging, and information encryption applications. However, so far, very limited schemes have been attempted for dynamic plasmonic color generation. In this paper, we demonstrate a scanning plasmonic color generation scheme, in which subwavelength plasmonic pixels can be laterally switched on/off through directional hydrogenation/dehydrogenation of a magnesium screen. We show several dynamic plasmonic color displays with different scanning functions by varying the number and geometries of the palladium gates, where hydrogen enters the scanning screens. In particular, we employ the scanning effects to create a dynamic plasmonic quick response code. The information cannot be decrypted by varying the polarization states of light or by accessing the physical features. Rather, it can only be read out using hydrogen as a decoding key. Our work advances the established design concepts for plasmonic color printing and provides insights into the development of optical information storage and anticounterfeiting features.

physics.app-ph↗

arXiv2021

Self-recording and manipulation of fast long-range hydrogen diffusion in quasifree magnesium

Understanding diffusion of large solutes such as hydrogen and lithium in solids is of paramount importance for energy storage in metal hydrides and advanced batteries. Due to its high gravimetric and volumetric densities, magnesium is a material of great potential for solid-state hydrogen storage. However, the slow hydrogen diffusion kinetics and the deleterious blocking effect in magnesium have hampered its practical applications. Here, we demonstrate fast lateral hydrogen diffusion in quasifree magnesium films without the blocking effect. Massive concomitant lattice expansion leads to the formation of remarkable self-organized finger patterns extending over tens of micrometers. Detailed visualization of diffusion fronts reveals that the fingers in these patterns follow locally the direction of hydrogen diffusion. Thus, the streamlines of the diffusion process are self-recorded by means of the finger pattern. By inclusion of fast hydrogen diffusion objects or local gaps, the resulting streamlines exhibit a clear analogy to optical rays in geometric optics. The possibility to spatially manipulate hydrogen diffusion opens an avenue to build advanced hydrogen storage systems, cloaking and active plasmonic devices, as well as prototype systems for computational models.

physics.app-ph↗

arXiv2021

DNA-assembled nanoarchitectures with multiple components in regulated and coordinated motion

Coordinating functional parts to operate in concert is essential for machinery. In gear trains, meshed gears are compactly interlocked, working together to impose rotation or translation. In photosynthetic systems, a variety of biological entities in the thylakoid membrane interact with each other, converting light energy into chemical energy. However, coordinating individual parts to carry out regulated and coordinated motion within an artificial nanoarchitecture poses challenges, owing to the requisite control on the nanoscale. Here, we demonstrate DNA-directed nanosystems, which comprise hierarchically-assembled DNA origami filaments, fluorophores, and gold nanocrystals. These individual building blocks can execute independent, synchronous, or joint motion upon external inputs. These are optically monitored in situ using fluorescence spectroscopy, taking advantage of the sensitive distance-dependent interactions between the gold nanocrystals and fluorophores positioned on the DNA origami. Our work leverages the complexity of DNA-based artificial nanosystems with tailored dynamic functionality, representing a viable route towards technomimetic nanomachinery.

physics.bio-ph↗

arXiv2021

Reconfigurable Multistate Optical Systems Enabled by VO2 Phase Transitions

Reconfigurable optical systems are the object of continuing, intensive research activities, as they hold great promise for realizing a new generation of compact, miniaturized, and flexible optical devices. However, current reconfigurable systems often tune only a single state variable triggered by an external stimulus, thus, leaving out many potential applications. Here we demonstrate a reconfigurable multistate optical system enabled by phase transitions in vanadium dioxide (VO2). By controlling the phase-transition characteristics of VO2 with simultaneous stimuli, the responses of the optical system can be reconfigured among multiple states. In particular, we show a quadruple-state dynamic plasmonic display that responds to both temperature tuning and hydrogen-doping. Furthermore, we introduce an electron-doping scheme to locally control the phase-transition behavior of VO2, enabling an optical encryption device encoded by multiple keys. Our work points the way toward advanced multistate reconfigurable optical systems, which substantially outperform current optical devices in both breadth of capabilities and functionalities.

physics.app-ph↗

arXiv2018

DNA nanotechnology-enabled chiral plasmonics: from static to dynamic

In this Account, we discuss a variety of static and dynamic chiral plasmonic nanostructures enabled by DNA nanotechnology. In the category of static plasmonic systems, we first show chiral plasmonic nanostructures based on spherical AuNPs, including plasmonic helices, toroids, and tetramers. To enhance the CD responses, anisotropic gold nanorods with larger extinction coefficients are utilized to create chiral plasmonic crosses and helical superstructures. Next, we highlight the inevitable evolution from static to dynamic plasmonic systems along with the fast development of this interdisciplinary field. Several dynamic plasmonic systems are reviewed according to their working mechanisms.

physics.bio-ph↗

arXiv2018

Optically resolving the dynamic walking of a plasmonic walker couple

Deterministic placement and dynamic manipulation of individual plasmonic nanoparticles with nanoscale precision feature an important step towards active nanoplasmonic devices with prescribed levels of performance and functionalities at optical frequencies. In this Letter, we demonstrate a plasmonic walker couple system, in which two gold nanorod walkers can independently or simultaneously perform stepwise walking powered by DNA hybridization along the same DNA origami track. We utilize optical spectroscopy to resolve such dynamic walking with nanoscale steps well below the optical diffraction limit. We also show that the number of walkers and the optical response of the system can be correlated. Our studies exemplify the power of plasmonics, when integrated with DNA nanotechnology for realization of advanced artificial nanomachinery with tailored optical functionalities.

physics.bio-ph↗