CyberSec Research

Efficient chip-scale interconnects are essential for modern microelectronic-photonic systems, supporting high bandwidth and low-latency processing. Traditional wired links face high resistivity and latency, while millimeter-wave wireless solutions suffer from bandwidth congestion and interference. Terahertz (THz) plasmonic communication, based on surface plasmon polaritons (SPPs), offers high data rates and broad bandwidth, and is compatible with nanophotonic platforms. This work introduces a Binary Field-Driven Meta-Routing Method supported by a semi-analytical framework that models the tunable interaction between THz plasmonic phenomena and graphene's electromagnetic properties. By modulating graphene's impedance, the method enables dynamic coupling and routing of localized surface plasmon resonances (LSPRs) across a meta-network, facilitating real-time beam steering in chip-scale systems. Combining analytical conductivity models, coupled-mode theory, and algorithmic control, the approach enables predictive configuration of LSPR-based steering in reconfigurable graphene metasurfaces. Four meta-pixel antenna configurations Y-MetaRouter, MetaSwitcher, Penta-MetaEmitter, and CP-MetaCore are designed to support unidirectional radiation, bi-directional steering, frequency-driven transitions, and circular polarization, respectively. Chemical potential modulation creates reconfigurable LSPR pathways and virtual SPP channels. A Coupled-Mode Theory for Field-Driven LSPR Meta-Networks is proposed to model current distributions and predict far-field characteristics. Results show strong agreement between theory and full-wave simulations. A point-to-point meta-wireless link is analyzed, demonstrating scalability for low-latency, high-performance THz communication in WiNoC and chiplet applications. System-level metrics confirm feasibility for space-constrained, high-speed interconnects.

Surface Enhanced Raman Spectroscopy (SERS) is a highly sensitive and selective technique that greatly enhances the signal of an analyte, compared with its signal from classical Raman Spectroscopy, due to its interaction with a substrates surface. It has been shown that low concentration boron-doped graphene (B-graphene) enhances the Raman signal of simple organic molecules like pyridine. Recent studies also suggest that B-graphene can remain thermodynamically stable when doped with significantly higher concentrations of boron than previously observed. In this framework, we use quantum mechanical simulations to investigate the influence of dopant concentration and geometric distribution on the effectiveness of B-doped graphene as a SERS substrate, with glucose as analyte. By combining analysis of interatomic force constants and of phonon eigenvectors composition, we conclude that higher doping concentrations provide a larger enhancement to glucose's Raman signal, while the molecule orientation relative to the surface plays a fundamental role in the Raman response. We suggest that high concentration B-graphene presents itself as a potential substrate for SERS based detection of glucose, while the used phonon-based analysis can be promptly applied for the search of promising candidates as substrate materials for enhanced Raman response.

Single-photon emitters (SPE) in hexagonal boron nitride (h-BN) are promising for applications ranging from single-photon sources to quantum sensors. Previous studies exclusively focused on the generation and characterization of SPEs in relatively thick h-BN layers ($\geq$ 30 nm). However, for electrical and magnetic sensing applications, the thickness of the h-BN limits the attainable spatial resolution. Here, we report the observation of blue-wavelength emitters (B-centers) activated by electron beam irradiation in ultra-thin ($\simeq$ 3 nm) h-BN. These SPEs in ultra-thin flakes exhibit reduced brightness, broader zero-phonon line, and enhanced photobleaching. Remarkably, upon encapsulation in thicker h-BN, we restore their brightness, narrow linewidth 230$\mu$eV at 5K, resolution limited), suppress photobleaching, and confirm single-photon emission with $ g^{(2)}(0) < 0.4$ at room temperature. The possibility of generating SPEs in a few-layer h-BN and their subsequent incorporation into a van der Waals heterostructure paves the way for achieving quantum sensing with unprecedented nanometer-scale spatial resolution.

Radiation hardness of scintillating nanocomposites consisting of inorganic scintillating nanocrystalline powders dispersed in organic matrices was studied under electron, X-ray and {\gamma}-ray irradiation. Samples including pure press-compacted pellets of powder ZnO:Ga and YSO:Ce, and the nanocomposites of powder ZnO:Ga and YSO:Ce embedded in polystyrene matrix with different fillings were investigated. Effects of radiation on radioluminescence and other optical properties of studied materials were evaluated. Bright burn effect related to nanocrystalline powder scintillators was observed at lower doses. Radiation damage in nanocomposite materials is related to the formation of radicals in polystyrene matrix. Extent of radiation damage decreases with ZnO:Ga filling. Presented results show the importance of systematic and complex study of the radiation stability of composite scintillators.

Space-borne gravitational wave detection will open the observation window in the 0.1 mHz$-$1 Hz bandwidth, playing a crucial role in the development of cosmology and physics. Precise clock synchronization among satellites is essential for the accurate detection of gravitational wave signals. However, the independent clock counting mechanisms of each satellite pose a significant challenge. This work reports the mathematical model of clock asynchrony, which is mainly dominated by the constant term factor and the linear term factor. Moreover, it experimentally verifies the clock asynchronization technique based on a dual-phasemeter system. Through experimentation, the impacts of these two aspects of clock asynchrony were confirmed, and post-processing techniques were employed to reduce these impacts to as low as $\rm 2\pi \times 10^{-6} rad/Hz^{1/2}@ 3mHz$. Specifically, the constant term factor is measured by Time-delay Interferometry Ranging (TDIR), while the linear term factor can be gauged by clock transmission link. This study provides a reference for understanding the clock asynchrony mechanism and processing clock synchronization issues. Additionally, a low additional noise clock synchronization test system is introduced to support such measurements.

This work aims to model the hypersurface of the effective elastic modulus, \( E_{z, \text{eff}} \), and thickness, \( th_{\text{eff}} \), in corrugated boards. A Latin Hypercube Sampling (LHS) is followed by Gaussian Process Regression (GP), enhanced by EHVI as a multi-objective acquisition function. Accurate modeling of \( E_{z, \text{eff}} \) and \( th_{\text{eff}} \) is critical for optimizing the mechanical properties of corrugated materials in engineering applications. LHS provides an efficient and straightforward approach for an initial sampling of the input space; GP is expected to be able to adapt to the complexity of the response surfaces by incorporating both prediction and uncertainty. Therefore, the next points being generated and evaluated are based on the complexity of the hypersurfaces, and some points, especially those with higher variance, are more exploited and carry more importance. The performance of GP with EHVI is measured by Mean Squared Error (MSE). Prediction of GP resulted in \( \text{MSE}(E_{z, \text{eff}}) = 5.24 \, \text{kPa}^2 \) and \( \text{MSE}(th_{\text{eff}}) = 1 \, \text{mm}^2 \). GP possesses then improved accuracy and adaptability for future applications in structural optimization.

In river or tidal channels, cross-flow turbines can achieve higher blockage ratios than other turbine variants, and are therefore able to achieve higher efficiencies. Here, we experimentally investigate how array control strategies might further influence the efficiency of a high-blockage dual-rotor cross-flow turbine array. Array performance is evaluated under coordinated constant speed control, uncoordinated torque control, and coordinated intracycle speed control at blockage ratios of 35% - 55%. In contrast to prior work at lower blockage, the evaluated control strategies do not yield significant improvements in efficiency and intracycle control is found to generally reduce array performance. While these results suggest limited benefits to more advanced control strategies at high blockage, this has the benefit of simplifying the system design space for array-level control.

This study presents a simplified FEM modeling approach suitable for large structures made of corrugated boards, such as customized packages, based on a homogenization method, which is combined with correction factors for internal mechanisms. The homogenization process reduces computational time by transforming flute geometries into equivalent elastic models. In large deformations and in the presence of contact for a given geometry, the effective elastic modulus in the thickness direction, as well as the effective thickness of the structure, are corrected by two statistical Weibull distributions representing the contact and buckling mechanisms in a corrugated board. The Weibull parameters are obtained via experimental analysis, and such a process is then validated. The results demonstrate that the statistical parameters ($\beta_1 = 0.14$, $\beta_2 = 1.31$) can be used for the simplistic representation of corrugated boards, being computationally efficient. This research contributes to the optimization of corrugated packaging design, specifically by simplifying FEM models for faster yet equally accurate simulations.

Physics-consistent theoretical studies on RIS-parametrized wireless channels use models from multiport-network theory (MNT) to capture mutual-coupling (MC) effects. However, in practice, RIS design and radio environment are partially or completely unknown. We fill a research gap on how to estimate the MNT model parameters in such experimentally relevant scenarios. Our technique efficiently combines closed-form and gradient-descent steps, and it can be applied to multi-bit-programmable RIS elements. We discuss inevitable (but operationally irrelevant) parameter ambiguities. We experimentally validate our technique in an unknown rich-scattering environment parametrized by eight 8-bit-programmable RIS elements of unknown design. We experimentally evaluate the performance of RIS configurations optimized with the estimated MNT model and an MC-unaware cascaded model. While the models differ in accuracy by up to 17 dB, the end-to-end performance differences are small.

The interaction between light's angular momentum (AM) and material systems has unlocked new avenues in structured photonics, including in magneto-optical (MO) materials. While spin angular momentum (SAM) effects in MO systems are well-established, orbital angular momentum (OAM) introduces novel opportunities for new nonreciprocal light-matter interactions. In this study, we demonstrate a unique optical phenomenon where OAM states undergo state-specific nonreciprocal operation within an MO medium, reducing Faraday rotation. This effect arises from transverse momentum transfer into the material, inducing spin-orbit coupling (SOC) at a perturbed electronic transition rate. The resulting OAM-dependent optical SOC modifies the material's refractive index, directly linking structured light and MO response. Our findings extend previous observations of paraxial beams and reveal a deeper fundamental mechanism governing OAM-driven nonreciprocal interactions. These insights pave the way for OAM-selective nonreciprocal photonic devices, chiral optical logic, quantum memory elements, and ultrafast spintronic architectures. This work advances MO integration with structured light for enhanced control over photonic and spintronic systems.

Metamaterials are a new generation of advanced materials, exhibiting engineered microstructures that enable customized material properties not found in nature. The dynamics of metamaterials are particularly fascinating, promising the capability to guide, attenuate, and focus waves at will. Phononic metamaterials aim to manipulate mechanical waves with broad applications in acoustics, elastodynamics, and structural vibrations. A key bottleneck in the advancement of phononic metamaterials is scalability -- in design, simulation, and especially fabrication (e.g., beyond tens of unit cells per spatial dimension). We present a framework for scalable inverse design of spatially graded metamaterials for elastic wave guiding, together with a scalable microfabrication method. This framework enables the design and realization of complex waveguides including hundreds of thousands of unit cells, with the potential to extend to millions with no change in protocol. Scalable design is achieved via optimization with a ray tracing model for waves in spatially graded beam lattices. Designs are fabricated by photolithography and etching of silicon wafers to create free-standing microarchitected films. Wave guiding is demonstrated experimentally, using pulsed laser excitation and an interferometer for displacement measurements. Broadband wave guiding is demonstrated, indicating the promise of our scalable design and fabrication methods for on-chip elastic wave manipulation.

We present \textbf{GeQuLEP} (Germanium-based Quantum Sensors for Low-Energy Physics), a conceptual design for an advanced quantum sensing platform integrating high-purity germanium (Ge) crystals with engineered phononic crystal cavities. At cryogenic temperatures, these cavities naturally host dipole-bound states, effectively forming quantum dots coupled to radio-frequency quantum point contact (RF-QPC) readout systems. This innovative coupling approach promises ultra-sensitive phonon-mediated charge detection through phonon-induced charge displacement. GeQuLEP is specifically designed to achieve exceptionally low detection thresholds, theoretically enabling single primary phonon sensitivity with anticipated energy depositions as low as \textbf{0.00745~eV}. This unprecedented sensitivity, if realized experimentally, would provide unique access to searches for low-mass dark matter down to the keV/$c^2$ mass range via nuclear and electronic recoils. Additionally, GeQuLEP aims to facilitate the real-time detection of solar \textit{pp} neutrinos through coherent elastic neutrino--nucleus scattering (CE$\nu$NS). By combining phonon-based quantum transduction with quantum-classical hybrid readout schemes, the GeQuLEP architecture represents a scalable, contact-free phonon spectroscopy design that could significantly advance the capabilities of ultra-low-energy rare-event detection at the quantum limit.

Dried leaves in nature often exhibit curled and crumpled morphologies, typically attributed to internal strain gradients that produce dome-like shapes. However, the origin of these strain gradients remains poorly understood. Although leaf veins--particularly the midvein--have been suggested to influence shape formation, their mechanical role has not been systematically investigated. Here, we demonstrate that mechanical constraints imposed by the midvein play a crucial role in generating the diverse morphologies that emerge during leaf drying. Combining numerical simulations and theoretical analysis, we show that a uniformly shrinking leaf lamina constrained by a non-shrinking midvein gives rise to two distinct types of configurations: curling-dominated and folding-dominated morphologies. In the curling-dominated regime, both S-curled and C-curled shapes emerge, with C-curled configurations more commonly observed due to their lower elastic energy. In contrast, the folding-dominated regime features folding accompanied by edge waviness. Theoretical modeling reveals a linear relationship between midvein curvature and mismatch strain, consistent with simulation results. Moreover, we find that the morphological outcome is governed by the ratio of bending stiffnesses between the lamina and the midvein. We construct a comprehensive phase diagram for the transitions between different configurations. These findings provide a mechanical framework for understanding shape formation in drying leaves, offering new insights into natural morphing processes and informing the design of bio-inspired morphable structures.

Braiding has attracted significant attention in physics because of its important role in describing the fundamental exchange of particles. Infusing the braiding with topological protection will make it robust against imperfections and perturbations, but such topological braiding is believed to be possible only in interacting quantum systems, e.g., topological superconductors. Here, we propose and demonstrate a new strategy of topological braiding that emerges from non-Abelian topological insulators, a class of recently discovered multi-band topological phase. We unveil a mathematical connection between braiding and non-Abelian quaternion invariants, by which Bloch eigenmodes under parallel transport produce braid sequences protected by the non-Abelian band topology. The braiding is also associated with geometric phases quantized over half the Brillouin zone. This new type of non-Abelian topological braiding is experimentally realized in acoustic systems with periodic synthetic dimensions. The results show that the principle discovered here is a new strategy towards topological braiding and can be extended for other types of classical waves and non-interacting quantum systems.

We present an experimental protocol for the fabrication and characterization of scalable microarchitected elastic waveguides. Using silicon microfabrication techniques, we develop free-standing 2D truss-based architected waveguides with a maximum diameter of 80 mm, unit cells size of 100 micrometer, and minimum beam width of 5 micrometer, thus achieving scale separation. To characterize elastic wave propagation, we introduce a custom-built scanning optical pump-probe experiment that enables contactless excitation of elastic wave modes and full spatio-temporal reconstruction of wave propagation across hundreds of unit cells with sub-unit cell resolution. Results on periodic architectures show excellent agreement with finite element simulations and equivalent experimental data at larger length scales. Motivated by scalable computational inverse design, we fabricate a specific example of a spatially graded waveguide and demonstrate its ability to guide elastic waves along an arbitrary pre-designed path.

We show that microstructures built from non-magnetic conducting sheets exhibit an effective magnetic permeability, /mu_meff, which can be tuned to values not accessible in naturally occurring materials, including large imaginary components of /mu_meff. The microstructure is on a scale much less than the wavelength of radiation, is not resolved by incident microwaves, and uses a very low density of metal so that structures can be extremely lightweight. Most of the structures are resonant due to internal capacitance and inductance, and resonant enhancement combined with compression of electrical energy into a very small volume greatly enhances the energy density at critical locations in the structure, easily by factors of a million and possibly by much more. Weakly non-linear materials placed at these critical locations will show greatly enhanced effects raising the possibility of manufacturing active structures whose properties can be switched at will between many states

Portable quantum technologies require robust, lightweight apparatus with superior performance. For techniques dependent upon high-vacuum environments, such as atom interferometers and atomic clocks, 3D-printing enables new avenues to tailor in-vacuum gas propagation dynamics. We demonstrate intricate, fine-scale surface patterning of 3D-printed vacuum components to increase the rate at which gas particles collide with the surface. By applying a non-evaporable getter coating for use as a surface pump, we show that the patterned surface pumps gas particles 3.8 times faster than an equivalent flat areas. These patterns can be directly integrated into additively manufactured components, enabling application in close proximity to key experimental regions and contributing to overall mass-reduction. We develop numerical simulations that show good agreement with this result and predict up to a ten-fold increase in pumping rate, for realistic surface structures. Our work has direct applications in enabling passively-pumped portable quantum technologies, but also establishes 3D-printing as a powerful technique for the creation of optimized surface patterning to provide enhanced control over high-vacuum gas dynamics for a broad range of applications.

The present study investigates the linear and non-linear optical and magneto-optical properties of TeO$_2$-BaO-Bi$_2$O$_3$ (TeBaBi) glasses prepared by the conventional melt-quenching technique at 900 {\deg}C. Prepared glass composition ranges across the whole glass-forming-ability (GFA) region focusing on mutual substitution trends of constituent oxides, where TeO$_2$: 55-85 mol.%, BaO: 10-35 mol.%, Bi$_2$O$_3$: 5-15 mol.%. Studied glasses exhibit high values of linear ($n_{632} \approx$ 1.922-2.084) and non-linear refractive index ($n_2\approx$1.63-3.45$\times10^{-11}$ esu), Verdet constant ($V_{632} \approx$ 26.7-45.3 radT$^{-1}$m$^{-1}$) and optical band gap energy ($E_g \approx$ 3.1-3.6 eV). The introduction of TeO$_2$ and Bi$_2$O$_3$ results in increase of both linear/non-linear refractive index and Verdet constant, with a more pronounced influence of Bi$_2$O$_3$. Measured spectral dispersion of refractive index and Verdet constant were used for estimation of magneto-optic anomaly parameter ($\gamma \approx$ 0.71-0.92), which may be used for theoretical modelling of magneto-optic response in diamagnetic TeBaBi glasses. Additionally, the properties of the prepared TeBaBi glasses were directly compared to those of the TeO$_2$-ZnO-BaO glass system, which was prepared and characterized under similar experimental conditions. The compositional dependence of the refractive index in both glass systems was described using multilinear regression analysis, demonstrating high correlation and uniformity of estimation across the entire GFA region. This makes them highly promising for precise dispersion engineering and construction of optical devices operating from visible to mid-infrared spectral region.