ABSTRACT Quantum entanglement is a crucial resource in quantum information science, applying to quantum key distribution, quantum sensing, and quantum teleportation. However, generating macroscopic quantum entanglement in multimode optomechanical systems, where an optical mode couples to multiple degenerate or near‐degenerate vibrational modes, is a challenging task, as the entanglement is suppressed by the dark‐mode effect. In this paper, we propose a scheme to generate both bipartite and genuine tripartite entanglement in the system via periodic modulation. First, we consider a two‐oscillator optomechanical system in which time‐varying voltages applied to the oscillators enable the engineering of coupling pathways between the bright and dark modes, thus breaking the dark‐mode effect. Thermal phonons can be extracted by the coupling channels, so that bipartite and tripartite entanglement can be achieved at a nonzero temperature. Furthermore, we extend this scheme to an optomechanical system with oscillators, where the degenerate vibrational modes can entangle with the optical mode. Notably, the macroscopic quantum entanglement we obtain exhibits greater robustness against thermal phonons.

Dark mode has become a standard feature across digital interfaces due to its visual comfort and aesthetic appeal. However, most brand logos are originally designed for light backgrounds, and when directly applied to dark backgrounds, they often suffer from color distortion, reduced visibility, and visual discomfort. These issues can negatively impact both brand identity and user experience. This study aims to propose a systematic adjustment model to optimize brand logo colors in dark mode environments. The research consisted of two experiments. In the first experiment, 31 design-major students manually adjusted 18 fictitious logos with diverse colors on a black background. The analysis revealed systematic trends in color modification, with bright colors shifting toward darker values, dark colors becoming lighter, and chroma showing an overall reduction. Additionally, red and blue hues required hue-angle corrections. Based on these findings, a convergence surface for color adjustment was constructed using Kriging interpolation, leading to the development of a predictive model applicable to new logo colors. The second experiment evaluated the model through a preference survey with 89 participants, using a set of 36 logos, including 18 fictitious logos and 18 commercial logos. Participants compared original logos with those adjusted by the proposed model. The adjusted versions were generally preferred, with the effect being particularly pronounced for logos originally featuring dark colors. The proposed model offers design principles that ensure both brand consistency and visual comfort. By integrating perceptual evidence with empirical validation, this approach provides a stable method for maintaining brand color representation in digital environments and demonstrates applicability to a wider range of graphic elements in dark mode.

The phenomenon of electromagnetically induced transparency (EIT)-like in terahertz (THz) metasurfaces facilitates agile manipulation of electromagnetic wave transmission windows and the deceleration of light, rendering it suitable for applications in modulators, absorbers, slow light devices, and more. Traditional design methodologies focus on the coupling between bright-dark modes and bright-bright modes within the unit cell, leveraging interference cancellation effects to regulate electromagnetic wave transmission. Notably, the periodicity of the array structure also plays a pivotal role in modulating the amplitude and resonance intensity of the transparent window, a phenomenon termed lattice-induced transparency (LIT). In this paper, we introduce a gold nanorod structure and an S-shaped gold split-ring resonator supported on a vanadium dioxide (VO<sub>2</sub>) thin film to investigate LIT. Unlike conventional structures that solely consider single bright-bright or bright-dark mode coupling, our proposed structure incorporates both bright-bright and bright-dark modes coupling. Furthermore, the dark mode in our structure is not a conventional multipolar mode but rather a surface lattice resonance (SLR) arising from the coupling between lattice modes and the localized surface plasmon resonance (LSPR) of the structure itself.<br>Through the analysis of simulated transmission spectra for the individual gold nanorod and S-shaped split-ring structures, we observed that the gold nanorod exhibits LSPR at 0.985 THz, whereas the S-shaped split-ring structure demonstrates LSPR and SLR at 0.51 THz and 1.025 THz, respectively. When combined, these structures form transparent windows with transmission rates of 66.03% and 59.4% at 0.643 THz and 1.01 THz due to the interplay of bright-bright and bright-dark modes coupling. Upon examining the electric field distribution in the x-y plane, we found that the electric field energy is predominantly concentrated on the S-shaped split-ring.<br>To gain deeper insights into each resonance mode, we employed multipolar decomposition to quantify resonance scattering energy. Our findings revealed that both transparent windows are predominantly governed by electric dipole scattering energy. Further investigations showed that as the array structure’s period varies from 60 <i>μ</i>mto 95 <i>μ</i>m, the lattice mode progressively couples into the high frequency transmission valley (1.031 THz), giving rise to a high frequency hybrid mode (HFHM). The <i>Q</i> value of this mode initially increases and then decreases, peaking at 27 when the period is 84 <i>μ</i>m. Similarly, as the period continues to increase, the lattice mode couples into the low frequency resonance valley (0.76 THz), forming a low frequency hybrid mode (LFHM) with a <i>Q</i> value that reaches a maximum of 51 at 115 <i>μ</i>m—approximately an order of magnitude higher than that at a period of 60 <i>μ</i>m. Additionally, as the periodicity increases, the near field coupling effect between adjacent units diminishes, leading to the gradual disappearance of the two transparent windows.<br>To achieve active control over these transparent windows, we varied the conductivity of VO<sub>2</sub> from 20 S/m to 30000 S/m, resulting in a decrease in the transmission amplitudes of the two transparent windows to 37.58% and 3.39%, respectively. Finally, we investigated the slow light effect of the two transparent windows, comparing the maximum group delay between them, which was found to be 8.1 ps. The terahertz metasurface proposed in this study opens up avenues for the design of dynamically tunable sensing and slow light devices in the future.

Traditional electromagnetically induced transparency (EIT) typically exhibits low quality (Q) factors and limited tunability. Bound states in the continuum (BIC) offer a promising solution for achieving high-Q EIT. In this work, we engineer a high-Q EIT resonance on a silicon-membrane metasurface by coupling a quasi-BIC with a Brillouin zone folding guided mode resonance (BZF-GMR). In the unit cell of metasurfaces featuring dual rectangular nanoholes, asymmetric perturbation (rotating one nanohole) converts a symmetry-protected BIC, dominated by a toroidal dipole, into a high-Q quasi-BIC that functions as a dark mode. Simultaneously, it tunes a magnetic dipole-dominated BZF-GMR into the bright mode. Synergistic coupling between these modes produces a prominent EIT resonance, characterized by an 8.4 ps group delay and a high-Q of $5.9\times 10^{3}$ (corresponding experimental Q-factor of 250). Furthermore, the EIT resonance wavelength and Q-factor are precisely tuned by varying the asymmetry parameter. The design holds robustness against parameter variations. The fabrication and characterization of silicon metasurface samples validate our design approach. Our results demonstrate a reliable strategy for achieving a high-Q EIT resonance, with promising applications in slow light, high-sensitivity sensing, nonlinear enhancement, and ultrafast optical modulation.

Mapping Quantitative Data in Dark Mode: Need for Reversing Color Schemes?

Phase retardation differentially modulates the lifetimes and resonance of bright and dark plasmonic modes

Dark radial plasmonic modes of ultralong lifetime in a silver-sodium nanoantenna with dual broken symmetry

Abstract Dual‐band electrochromic devices (DECDs) can regulate the transmittance of visible (VIS) and near‐infrared (NIR) light, representing a significant advancement for smart windows. However, current DECDs are limited by a dearth of color options and the inherent challenges in achieving independent control over VIS and NIR transmission. Herein, this study develops a multi‐color, multi‐mode dual‐band zinc anode electrochromic device (ZECD) using phytic acid‐doped polyaniline (PANI). Due to PANI's unique redox properties, this device produces colors of bright yellow, yellow, blue, and purple, enhancing visual appeal. More importantly, by leveraging the nonlinear relationship between polariton/bipolaron concentration in PANI and applied potential, the device can operate in bright, cool, dark, and warm modes, allowing independent control of VIS and NIR lights. Additionally, introducing phytic acid effectively reduces PANI's bandgap, optimizes its molecular electrostatic potential distribution, and significantly improves the redox reaction reversibility. Therefore, the ZECD shows high transmittance modulating ability (49.9% at 530 nm, 22.1% at 1000 nm), fast response times (61.4 and 19.2 s at 530 nm, 51.6 and 26.0 s at 1000 nm for bleaching and coloring, respectively) and excellent cycling durability (10 000 cycles with 63.2% retention at 530 nm, 70.9% retention at 1000 nm).

I-Quiz is an interactive web-based platform for conducting real-time quizzes in classrooms, events, or training sessions. The system allows the quiz host to create, manage, and smoothly execute quizzes while enabling the participants to join using either a unique PIN or QR code. I-Quiz focuses on simplicity, scalability, and engagement through its responsive user interface, dark mode, image-based questions, and real-time leaderboard. The application supports up to 200 concurrent players on mid-range server configurations and can scale further with improved hosting resources. It is an open-source project with a focus on self-hosting to offer flexibility and privacy for educators and institutions looking to keep their quiz data private.

Abstract A hybrid bilayer metasurface is prepared by placing a flexible metallic metasurface sticker onto another dielectric metasurface on solid substrate and the optical coupling between the two metasurfaces is investigated. The top layer supports a bright out‐of‐plane quadrupole surface lattice resonance (QSLR), while the bottom layer supports a dark quadrupole mode. When stacked together, they couple into two hybridized modes, symmetric and anti‐symmetric QSLRs. It is found that the splitting width, as well as the nature of these modes, depends on the spacer layer thickness t . The long decay length of the QSLR along the z ‐direction and its slow variation with t suggest that the interlayer coupling is mediated not by a local gap mode but by a nonlocal, extended mode. A key consequence of this nonlocal coupling is the insensitivity of the resonances to the lateral misalignment of the two layers. This alignment‐free property is highly advantageous for designing bilayer metasurfaces. Furthermore, it is demonstrated that photoluminescence enhancement from an emitter embedded in the spacer layer: The large field accumulation associated with the symmetric QSLR led to a remarkable photoluminescence enhancement up to 60 times compared to the bare spacer layer on the substrate. These findings pave the way toward quasi‐3D metasurfaces formed by stacking individual layers with precisely tuned interlayer distances, offering a promising approach for future photonic elements with integrated functionalities.

Electrochromic (EC) devices based on structurally designable and color-tunable EC molecules can dynamically regulate light-heat transmittance via the charge-transfer mechanism, yet face challenges of limited near-infrared (NIR) absorption, long-term instability, and restricted modulation modes. Here, we show that π-stacking of heteroaromatic tri-pyridine molecules with a 1,3,5-triazine core (H-TriPy) enhances molecular conjugation, significantly augments NIR absorption, and enables dual-band modulation with improved visual comfort. The three pyridine-based redox centers facilitate multi-step electron transfer, enabling multi-modal EC regulation, including bright, cool, and dark modes. Incorporation of a fluorinated ionic liquid into EC organogels inhibits irreversible π-stacking of high-concentration H-TriPy. Consequently, H-TriPy-based EC devices achieve neutral-colored states with near-zero transmittance as low as 3.7% in both visible and NIR ranges and maintain high switching stability of over 89.1% retention after 100,000 cycles. Furthermore, large-area EC devices exhibit uniform tinting and reliable stability, underscoring their potential for energy-efficient green buildings.

Quasi-bound states in the continuum in dielectric metasurfacessupport sharp Fano resonances that emerge from the interference betweenbrightand dark modes. We exploit this modal interplay to demonstrate tunablethird-harmonic emission, controlled through the driving pulse’swavelength and intensity. Our experiments show imbalances in third-harmonicdiffraction patterns and non-Gaussian third-harmonic spectral featuresthat exhibit strong variations near the Fano resonance. We explainthe observations via a coupled-oscillator model that captures theinterplay between the driving field and the nonlinear response ofthe modes, explaining our observations and providing a predictiveframework for optimizing the third-harmonic diffraction efficiency.These results establish pulse-engineered metasurfaces as a powerfulplatform for nonlinear wavefront shaping and frequency conversionapplications while simultaneously serving as a warning that pulseproperties play a vital role in metasurface function design.

Mobile applications have been seamlessly integrated into our daily lives. When using mobile devices, the energy efficiency of these applications plays a pivotal role in enhancing the user experience. However, it is noteworthy that incorporating power conservation strategies into the toolkit of user-interface (or UI) developers for mobile applications receives almost none research attention. To address the unique requirements for UI developers, this manuscript studies the fusion of power conservation techniques and UI guidance principles to formulate an innovative framework aimed at conserving power consumption within UI. The power conservation framework begins with the extraction of displayed component configuration, drawing from UI previews without depending on any development environment and deployment equipment, during the development phase. Subsequently, we evaluate the UI guidance of the displayed components, taking into consideration the human visual systems. To recommend a power-saving configuration to developers, the final step generates a power-saving configuration that not only curtails power consumption but also preserves the global and local guidance. To validate the efficacy of our framework, we conducted evaluations using eight distinct UI previews, including light and dark modes, on a commercial smart phone. The results obtained from these evaluations are very promising.

Abstract A single-layer graphene structure is put forward to generate quadruple plasmon-induced transparency (PIT) at the terahertz frequency by coupling the bright-dark mode and bright-bright mode originated from five graphene strips. Based on the research on the electric field intensity of the PIT transparent window, it is suggested that intense fatal interference occurs among the bright and dark modes. The PIT reaction of the structure is analyzed and simulated with the coupled mode theory (CMT) and the finite difference time domain (FDTD) approach. Tunable multi-frequency switching is achieved under this quadruple transparency effect, since the maximum modulation depth (MD) is as high as 95% and the minimum insertion loss (IL) is 0.17 dB. Besides, the time delay and the group refractive index within the PIT windows can be up to 0.744 ps and 722, respectively. The proposed structure shows another fascinating ability to be sensitive to the nearby refractive index with the sensitivity of up to 0.91 THz/RIU. Therefore, this structure offers another novel thinking to design the multichannel switches, slow light instruments, and sensors in the terahertz band.

Abstract Metasurfaces that support bound states in the continuum (BICs) enable extreme spectral selectivity by suppressing radiative leakage; controlled symmetry breaking converts ideal BICs into quasi-BICs with finite yet ultra-high quality factors. Here, we design and numerically validate an all-dielectric silicon metasurface on SiO₂ that, under normal incidence, supports five quasi-BIC resonances in the 0.8–1.0 THz band. The metasurface unit cell comprises two semi-elliptical silicon elements; introducing a narrow slit in one element perturbs the symmetry and couples the otherwise dark modes to free space. Transmission and eigenmode analyses reveal five sharp resonance dips in the 0.8–1.0 THz band. We harness the quasi-BIC resonances excited under TE polarization for refractometric sensing by placing an analyte layer above the metasurface and quantify performance vs. analyte refractive index (1.4–1.5) and thickness (0–150 μm). The device attains a maximum sensitivity of 169.6 GHz RIU⁻¹ and a figure of merit (FOM) of 3.818 × 10 3 RIU −1 and a Q-factor of 3.42 × 10 4 owing to strong near-field confinement in the slit-perturbed element. The straightforward geometry, multi-resonant operation, and compatibility with dielectric microfabrication provide a practical route to multi-channel THz sensors. Our results establish design guidelines for engineering quasi-BICs at THz frequencies and for tailoring their spectral response to maximize sensing performance.

ABSTRACT The Zoro Chan Chatbot is an intelligent, web-based conversational platform developed to simulate real-time human-like conversations, offering an experience similar to advanced AI chatbots such as ChatGPT and DeepSeek. The system integrates a secure and efficient user authentication module that allows users to register or log in through the index page. Upon successful authentication, users are redirected to an interactive chat interface, where they can communicate with the chatbot through text messages. It supports key features such as light and dark mode switching, chat history management, and a “New Chat” option that enables users to start fresh conversations easily. In addition, a user profile management system allows users to update their email, change passwords, or delete accounts securely Thorough testing was carried out on all modules, including login, registration, and chatbot interaction, to ensure accuracy, performance, and security.

Abstract Direction‐dependent control of propagating electromagnetic radiation plays a crucial role in emerging photonic technologies, including isolators, circulators, detectors, and sensors. Typically, the directional control is achieved through nonreciprocal mechanisms involving magnetic biasing, spatiotemporal modulation, or nonlinear effects. However, incorporation of these techniques into the terahertz (THz) regime is cumbersome due to the material limitations and integration complexity. In this context, a planar metasurface design composed of geometrically asymmetric split ring resonators (SRRs) is presented, enabling unidirectional reflection. The asymmetry is induced by laterally displacing the capacitive gap in SRRs. The geometrical asymmetry in SRR induces asymmetric radiative loss, resulting in strong reflection from one direction and near‐complete suppression from the opposite. This thorough investigations demonstrate a reduction in resonance intensity (and resonance Q‐factor) with increasing geometric asymmetry, indicating redistribution of energy stemming from radiative loss engineering. The demonstrated metasurface designs enable controlled unidirectional reflection by accessing dark modes through introducing asymmetry in well accepted SRR‐based planar metasurface configuration.

Color Adjustment of Brand Logos for Dark Mode Display

Strong coupling between plasmons and excitons in transition metal dichalcogenides enables room-temperature plexciton formation, providing a crucial platform for investigating Bose-Einstein condensation, low-threshold nanolasers, and ultrafast optical switches. Plexcitons can be produced by far-field optical excitation and near-field electron beam excitation, while electron beam excitation enables the detection of dark plasmon modes and their spatial imaging. Using the boundary element method with a coupled harmonic oscillator model, electron energy loss spectroscopy of silver nanotriangles, WS2, and their composite system is simulated. Our numerical results are consistent with the corresponding experiments. From the charge distributions of silver nanotriangles in electron beam excitation, the dipole configurations corresponding to bright and dark plasmon modes are identified. The coupling mechanism of excitons and plasmons in the composite structure is analyzed. Additionally, the origin of asymmetry in spatial imaging maps of electron loss from plexcitons is clarified, and the proportions of plasmons and excitons in plexcitons produced by different detunings are analyzed theoretically. This study provides guidance for further experimental and theoretical research on strong coupling in analogous composite systems.

ABSTRACT Geoinformation is vital in many fields, especially where low-light environments and device energy efficiency are concerns. This study examined how modifying cartographic feature symbology – through color adjustments and textures – affects digital map usability in such conditions. Two styles were tested: a high-value color palette (light mode) and a low-value palette (dark mode). Both were presented to 367 participants in a controlled low-light environment, where they completed tasks related to cartographic objectives (identification, comparison, classification, and association) and responded to a questionnaire evaluating efficacy, efficiency, and satisfaction. The results showed no statistically significant difference in efficacy, as both styles attained similar accuracy rates. However, the light map yielded faster completion times, indicating higher efficiency. Meanwhile, 71.66% of participants preferred the dark map for visual comfort and reduced eye strain, reflecting higher satisfaction without compromising efficacy. Consequently, overall usability can be viewed as equivalent, as altering color and texture enabled users to maintain adequate information comprehension in low-light conditions. These findings suggest that adopting dark-themed maps may be advantageous in specific contexts. Hence, users can weigh convenience and preferences to best meet application requirements.