Solid-state Array Research Articles

(Invited) Plasmonic Metasurfaces Based on Epsilon-Near-Zero Materials

We report work on tunable plasmonic metasurfaces exploiting epsilon-near-zero effects in metal-oxide-semiconductor structures fabricated using conductive oxides. The tunable metasurfaces comprise subwavelength pixels that produce no grating diffraction and are used in reflection to control the magnitude and phase of the reflected beam. Applications include optical phased arrays, spatial light modulators, beam steering devices and wavefront shaping devices.Resonant nanometallic structures, such as plasmonic nanoantennas, are essential to convert light to surface plasmon-polaritons (SPPs) localized to ultra-small volumes. Such structures can provide highly enhanced fields, strong confinement, high surface sensitivity, and can double as a device electrode for applying voltages or passing currents to active regions in optoelectronic devices. In optoelectronics, plasmon enhancement can be exploited for high-performance electro-optic modulators and beam-steering devices [1-7].Fig. 1 shows an electrically-tunable plasmonic metasurface on fused silica [7]. The metasurface consists of an array of Au dipole nanoantennas contacted perpendicularly by electrical contact lines (Fig. 1(b)). The contact lines are centred on the nanoantennas (dipoles), which ensures that they are minimally invasive optically, due to their orthogonal alignment relative to the incident polarisation (along the nanoantenna axes). The nanoantennas are connected to an electrical fan-out structure (Fig. 1(a)) and coated with a HfO2 layer then an ITO layer (Fig. 1c)), and finally by a metal mirror structure (Fig. 1(d)). Electrically the structure operates as a MOS capacitor (Au-HfO2-ITO) with the top Au mirror structure also acting as the Ohmic contact to the ITO.When driven into strong accumulation, the ITO enters the epsilon-near-zero regime [6] resulting in large changes in the resonant behaviour of the nanoantennas. The structure produces a reflection coefficient at telecom wavelengths (l 0 ~ 1550 nm) that varies significantly in phase with applied voltage but maintains a constant reflectance [7]. The individual pixels (meta-atoms) in this structure are subwavelength such that grating diffraction upon reflection is completely avoided. The structure forms the basis of a solid-state optical phased array or a spatial light modulator which find application in beam steering and wavefront shaping devices.References Berini, P., “Optical Beam Steering Using Tunable Metasurfaces,” ACS Photonics, Vol. 9, pp. 2204-2218, 2022Calà Lesina, A., Goodwill, D., Bernier, E., Ramunno, L., Berini, P., “Tunable Plasmonic Metasurfaces for Optical Phased Arrays,” IEEE J Sel. Top. Quant. Electr., Vol. 27, 4700116, 2021Calà Lesina, A., Goodwill, D., Bernier, E., Ramunno, L., Berini, P., “On the performance of optical phased array technology for beam steering: effect of pixel limitations,” Opt. Express, Vol. 28, pp. 31637-31657, 2020Rashid, S., Walia, J., Northfield, H., Hahn, C., Olivieri, A., Calà Lesina, A., Variola, F., Weck, A., Ramunno, L., Berini, P., “Helium ion beam lithography and liftoff,” Nano Futures, Vol. 5, 025003, 2021Dhingra, N., Mehrvar, H., Berini, P., “Broadband polarization-independent plasmonic modulator on a silicon waveguide,” Optics Express, Vol. 31, pp. 22481-22496, 2023Shabaninezhad, M., Ramunno, L., Berini, P., “Tunable plasmonics on epsilon-near-zero materials: the case for a quantum carrier model,” Optics Express, Vol. 30, pp. 46501- 46519, 2022Mayoral Astorga, L. A., Shabaninezhad, M., Northfield, H., Ntais, S., Rashid, S., Lisicka-Skrzek, E., Mehrvar, H., Bernier, E., Goodwill, D., Ramunno, L., Berini, P., “Electrically tunable plasmonic metasurface as a matrix of nanoantennas,” Nanophotonics, Vol 13, pp. 901-913, 2024 Figure 1

End-fire optical phased array for passive beam steering on thin-film lithium niobate.

Autonomous driving technology has put forward higher requirements for sensors, including light detection and ranging. An optical phased array (OPA) is a viable solution, and numerous efforts have been made in this area. For its outstanding optical properties such as linear electro-optic effect and low optical loss, lithium niobate exhibits great potential and unique advantages in solid-state light-emitting arrays. Here we propose and experimentally demonstrate an end-fire optical phased array on a thin-film lithium niobate (TFLN) for passive beam steering. Furthermore, based on this work, we propose a three-line optical phased array to achieve a larger beam steering range. Our results provide a solution for the integrated optical phased array that shows potential in sensing and imaging with reduced size and power.

Ion Transport in Multi-Nanochannels Regulated by pH and Ion Concentration.

Nanochannels are a powerful technique for detecting a wide range of biomolecules without labeling. The ion transport phenomena in nanochannel arrays differ from those in single nanochannels and are caused by interchannel communication. This study uses a fully coupled Poisson-Nernst-Planck (PNP) and Navier-Stokes model to investigate ion transport in nanochannel arrays. Instead of being set at a constant value, the surface charge density used in this study is established by the protonation and deprotonation of the silanol groups that are present on the walls of the silicon-based nanochannels. The surface charge density of the nanochannel walls varies with the number of nanochannels, the channel lateral distance, and the background solution properties, which consequently influence the ionic concentration distribution, flow velocity, and electric field strength. For example, in different numbers of nanochannel systems, the ion concentration in nanochannels is not much different, but it is different in reservoirs, especially near the openings of nanochannels. The number of nanochannels and the distance between nanochannels can also affect the formation of electro-convective vortex zones under certain conditions. These findings can aid in optimizing the nanochannel array design by regulating the number and distance of nanochannels and facilitating the construction of solid-state nanochannel arrays with any desired nanochannel dimensions.

Improved charge separation by anatase TiO2 nanorod arrays for efficient solid-state PbS quantum-dot-sensitized solar cells

To improve the charge separation and transporting between PbS/TiO2 interface in PbS quantum-dot-sensitized solar cells, a 400 nm length anatase TiO2 nanorod array was successfully prepared by the conversion from ZnO nanorod array immersed in a 75 mM ammonium hexafluorotitanate acid solution. The influence of different immersion time on the microstructure, crystal phase and light absorption of the anatase TiO2 nanorod arrays were systematically studied. The PbS quantum dots (QDs) were deposited on the anatase TiO2 nanorod array via spin-coating-assisted successive ionic layer absorption and reaction (spin-SILAR) procedure using 5 mM PbI2 precursor solution, 5 mM Na2S·9H2O solution and 1% EDT/ethanol (1/99, v/v) solution. The solid-state PbS QD-sensitized anatase TiO2 nanorod array solar cell with the structure of FTO/TiO2 compact layer/PbS QD-sensitized anatase TiO2 nanorod array/spiro-OMeTAD/Au was assembled for the first time, and the champion device exhibited a photoelectric conversion efficiency of 5.47% with an open-circuit voltage of 0.62 V, a short-circuit photocurrent density of 13.71 mA cm-2 and a fill factor of 64.28%.

Highly sensitive miRNA detection of early-stage laryngeal carcinoma using a solid-state Au nanocone arrays fabricated LoC-SERS analysis system coupled with target-triggered dual cycle amplification strategy

Herein, with a target-triggered dual cycle amplification strategy, a novel lab-on-a-chip-based surface-enhanced Raman scattering (LoC-SERS) analysis system was established to analyze miRNAs quantitatively. Due to a more substantial complementary pairing effect, the presence of targets can replace the single-stranded DNA S1 (S1) from the single-stranded DNA F1 (F1) and single-stranded DNA S2 (S2) can replace and release the targets similarly. Thus, target can cyclically trigger the cycle Ⅰ and release S1 continuously. Cycle Ⅱ is the catalyzed hairpin assembly (CHA) event between the hairpin DNA 1 and hairpin DNA 2, which can connect the Ag-Au nanorods (Ag-AuNRs) to the surface of solid-state Au nanocone arrays (AuNCAs). Owing the dual cycle amplification strategy, localized surface plasmon resonance (LSPR) can be excited and significantly magnify the local electromagnetic field for SERS signal enhancement. Thus, ultrasensitive detection of miR-21 and miR-106b was achieved with the limit of detection as low as aM level. Attributed to the hydrophilic treatment and the design of capillary pump, the detection can be finished without any external pumps. Moreover, the system exhibited good practicability in the analysis of real serum samples obtained from Laryngeal carcinoma (LC) patients and healthy subjects. Therefore, the system is a promising candidate in clinical application and exhibited potential for the prediction, diagnosis, monitoring, and staging of LC.

Solid-State Au Nanocone Arrays Substrate for Reliable SERS Profiling of Serum for Disease Diagnosis.

Surface-enhanced Raman scattering (SERS) is a widely used rapid and noninvasive method for detecting biological substances in serum samples and is commonly employed in disease screening and diagnosis. Solid-state nanoarray SERS substrates used in serum detection may cause spectral instability due to imperfections in the detection method. For the purpose of identifying optimal detection conditions, various dilution levels of the serum were tested in this study. The study found that a complete and stable serum SERS spectrum can be obtained when the serum is diluted by a factor of 50. The study reports the successful preparation of an Au nanocone array (Au NCA) plasmonic substrate with a uniform, controllable microstructure and high activity, achieved through a combination of PS colloidal sphere template-assisted reactive ion etching (RIE) process and magnetron sputtering deposition technology. Based on this substrate, a standard detection scheme was developed to obtain highly stable and repeatable serum SERS spectra. The study verified the reliability of the optimized serum detection scheme by comparing the SERS spectra of serum samples from healthy individuals and gastric cancer patients, and confirmed the potential benefits of the scheme for disease screening and diagnosis.

Tailoring ion dynamics in energy storage conductors for ultra-stable, high-performance solid-state microsupercapacitor array

All-solid-state electrochemical energy storage (EES) devices with prolonged lifetime, operational stability, and mechanical flexibility can be a promising route to powering up wearable electronics. However, conventional EES devices have been often hindered by a gradual decrease in energy capacity due to low ionic conducting electrolytes, non-suitable electrode materials, or poor electrode/electrolyte interfaces. Herein, we propose a harmonization of the molecular-level tailoring of ionic gel polymer electrolyte (IGPE) and graphene-based electrodes, significantly improving and sustaining the electrochemical performance (11.9 μWh cm−2) of EES microsupercapacitor (MSC) devices. Our optimized MSC device based on ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIM-FSI) and interdigitated reduced-graphene oxide (rGO) electrode array maintains 99 % of the initial electrochemical capacity even after 20,000 cycles, also demonstrating the excellent mechanical flexibility (bending radius up to 4 mm) and environmental stability (>30 days) of the MSC-based array. Molecular-level simulation and spectroscopic atomic analysis revealed noticeably lower residual ionic liquid (IL) molecules of EMIM-FSI, compared to EMIM-trifluoromethyl FSI, between the graphene-based layers of electrodes during the charge/discharge cycles. Therefore, our optimization strategy and findings will pave the way to accomplish next-generation of all-solid-state EES devices with ultra-high operational stability, powering wearable electronics.

Solid-State Quad-Nanopore Array for High-Resolution Single-Molecule Analysis and Discrimination.

The ability to detect and distinguish biomolecules at the single-molecule level is at the forefront of today's biomedicine and analytical chemistry research. Increasing the dwell time of individual biomolecules in the sensing spot can greatly enhance the sensitivity of single-molecule methods. This is particularly important in solid-state nanopore sensing, where the detection of small molecules is often limited by the transit dwell time and insufficient temporal resolution. Here, a quad-nanopore is introduced, a square array of four nanopores (with a space interval of 30-50nm) to improve the detection sensitivity through electric field manipulation in the access region. It is shown that dwell times of short DNA strands (200bp) are prolonged in quad-nanopores as compared to single nanopores of the same diameter. The dependence of dwell times on the quad-pore spacing is investigated and it is found that the "retarding effect" increases with decreasing space intervals. Furthermore, ultra-short DNA (50bp) detection is demonstrated using a 10nm diameter quad-nanopore array, which is hardly detected by a single nanopore. Finally, the general utility of quad-nanopores has been verified by successful discrimination of two kinds of small molecules, metal-organic cage and bovine serum albumin (BSA).

A differential evolutionary chromosomal gene expression programming technique for electronic nose applications

The intelligent system applications require automated data-driven modeling tools. The performance consistency of modeling tools is very essential to reduce the need for human intervention. Classical Gene Expression Programmings (GEPs) employ predefined genetic rules for the node-based evolution of expression trees in the absence of optimal numerical values of constant terminals, and these shortcomings can limit the search efficiency of expression trees. To alleviate negative impacts of these limitations on the data-driven GEP modeling performance, a Differential Evolutionary Chromosomal GEP (DEC-GEP) algorithm is suggested. The DEC-GEP utilizes the Differential Evolution (DE) algorithm for the optimization of a complete genotype of expression trees. For this purpose, a modifier gene container, which stores numerical values of constant terminals, is appended to the frame of GEP chromosome, and this modified chromosome structure enables simultaneous optimization of expression tree genotypes together with numerical values of constant terminals. Besides, the DEC-GEP algorithm can benefit from exploration and exploitation capabilities of the DE algorithm for more efficient evolution of GEP expression trees. To investigate consistency of the DEC-GEP algorithm in a data-driven modeling application, an experimental study was conducted for soft calibration of the low-cost, solid-state sensor array measurements, and results indicated that the DEC-GEP could yield dependable CO concentration estimation models for electronic nose applications.

Optimal architecture artificial neural network model design with exploitative alpha gray wolf optimization for soft calibration of CO concentration measurements in electronic nose applications

The low-cost and small size solid-state sensor arrays are suitable to implement a wide-area electronic nose (e-nose) for real-time air quality monitoring. However, accuracy of these low-cost sensors is not adequate for precise measurements of pollutant concentrations. Artificial neural network (ANN) estimation models are used for the soft calibration of low-cost sensor array measurements and significantly improve the accuracy of low-cost multi-sensor measurements. However, optimality of neural architecture affects the performance of ANN estimation models, and optimization of the ANN architecture for a training data set is essential to improve data-driven modeling performance of ANNs to reach optimal neural complexity and improved generalization. In this study, an optimal architecture ANN estimator design scheme is suggested to improve the estimation performance of ANN models for e-nose applications. To this end, a gray wolf optimization (GWO) algorithm is modified, and an exploitative alpha gray wolf optimization (EA-GWO) algorithm is suggested. This modification enhances local exploitation skill of the best alpha gray wolf search agent, and thus allows the fine-tuning of ANN architectures by minimizing a multi-objective cost function that implements mean error search policy. Experimental study demonstrates the effectiveness of optimal architecture ANN models to estimate CO concentration from the low-cost multi-sensor data.

Muon track reconstruction in a segmented bolometric array using multi-objective optimization

Recent advances in segmented solid-state detector arrays for rare-event searches have allowed the technology to approach the ton-scale in detector mass and the scale of meters in size. Often focused around searches for neutrinoless double-beta decay or direct dark matter detection, such experiments also have the capability to search for exotic particles that leave track-like signatures across their volume. However, the segmented nature of such detector arrays often sets the spatial resolution and makes the problem of reconstructing track-like paths non-trivial. In this paper, we present an algorithm that improves reconstruction of track-like events in segmented detectors using multi-objective optimization — a computational technique that optimizes more than one cost function at a time without specifying a quantitative weighting between them. Such a technique allows the reconstruction of tracks through a detector and the determination of path-lengths through individual elements. When combined with the reconstructed energy depositions in each element this allows for a calculation of the stopping power of track-like particles and opens the door to searches for particles with abnormal stopping power like monopoles or lightly-ionizing particles (LIPs). Results are presented which evaluate the precision of the reconstruction tools as they currently stand against Monte Carlo generated data. The algorithm is presented in the context of the CUORE experiment, but has applications to other segmented calorimeter detectors.

Hydrophobic and Rapid-Response Sensor Inks: Array-Based Fingerprinting of Perfumes.

Counterfeited perfumes mixed with inexpensive additives for commercial purposes pose a great threat to cosmetic market competition and human health. Herein, a 24-element, solid-state colorimetric sensor array employing chemo-responsive dye inks for accurate discrimination of a variety of fragrance bases and "sniffing out" real perfumes from adulterated samples was first reported. The physiochemical robustness and gas response kinetics of the sensor array were optimized with the streamlined design of the channel geometry and hydrophobic modification of the sensor substrate. A unique and distinguishable color change profile was obtained within 2 min exposure of diluted vapor that enabled clear fingerprinting of chemically similar perfume samples. Four commercial perfume products were successfully distinguished and categorized according to their similarity to relevant perfume bases using chemometric methods including hierarchical clustering and principal component analysis. The sensor array also allows the discrimination of ethanol-diluted fragrance bases from the pristine sample, revealing its potential for quality assurance of perfumes and other cosmetics. Such easy-to-use, disposable, and miniaturized chemical sensing detectors therefore prove exceptionally valuable for fast analysis of luxuries such as perfumes and other industrial products with complex chemical compositions.

Crystalline paramagnetic supramolecular 2D-polymer of the tetra(4-pyridyl)porphyrin and terbium(III) complex.

A new promising method for the preparation of crystalline 2D polymers based on tetra(4-pyridyl)porphyrin has been developed. Radical anion {H2T(4-Py)P˙-} species are used as the starting material. A new solid-state supramolecular array [{H2T(4-Py)P}·{TbIII(TMHD)3}2]·2.84C6H14 (1) in which porphyrin units are bridged with TbIII ions to form a self-assembled 2D polymer has been obtained. The complex contains neutral porphyrin macrocycles, which is supported by optical and magnetic data. High-spin paramagnetic TbIII ions are weakly antiferromagnetically coupled in accordance with rather long distances between them.

Real-Time Edge Neuromorphic Tasting From Chemical Microsensor Arrays.

Liquid analysis is key to track conformity with the strict process quality standards of sectors like food, beverage, and chemical manufacturing. In order to analyse product qualities online and at the very point of interest, automated monitoring systems must satisfy strong requirements in terms of miniaturization, energy autonomy, and real time operation. Toward this goal, we present the first implementation of artificial taste running on neuromorphic hardware for continuous edge monitoring applications. We used a solid-state electrochemical microsensor array to acquire multivariate, time-varying chemical measurements, employed temporal filtering to enhance sensor readout dynamics, and deployed a rate-based, deep convolutional spiking neural network to efficiently fuse the electrochemical sensor data. To evaluate performance we created MicroBeTa (Microsensor Beverage Tasting), a new dataset for beverage classification incorporating 7 h of temporal recordings performed over 3 days, including sensor drifts and sensor replacements. Our implementation of artificial taste is 15× more energy efficient on inference tasks than similar convolutional architectures running on other commercial, low power edge-AI inference devices, achieving over 178× lower latencies than the sampling period of the sensor readout, and high accuracy (97%) on a single Intel Loihi neuromorphic research processor included in a USB stick form factor.

On-site Chemosensor Arrays for Qualitative and Quantitative Detection with Imaging Analysis

Chemosensor arrays utilizing powerful chemometric techniques, which are inspired by the olfactory system, enable the visualization of multidimensional chemical information. However, such array systems have not been applied to on-site analyses. In this review, we describe approaches to realizing chemosensor arrays for on-site analyses, which are integrated systems of imaging analysis and solid-state sensor array chips constructed using π-conjugated polymers in a hydrogel or self-assembled chemosensors on a filter paper. The design of experiments has been employed for the optimization of the chip designs to obtain a uniform color contrast for reproducible imaging analysis. Moreover, the unique structural properties of chemosensors can provide information-rich optical responses, thus requiring only chips with a small number of chemosensors that discriminate many chemical species simultaneously. The solid-state minimized chemosensor array chips designed on the basis of a statistical method successfully quantified chemical species and their concentrations in real samples without any pretreatments. Thus, we believe that our strategy would pave the way to realizing chemosensors used in real-world scenarios.

Computer High-Voltage Corona Recognition Analysis Based on Ultraviolet Imaging Technology

Ultraviolet-visible high-voltage corona recognition tends to have no mechanical moving parts, integration and solid state to complete the complex, high-temperature and high-pressure detection site. At the same time, it must have the characteristics of fast detection speed, reliable data and high reproducibility. Among them, the miniaturization and solidification of ultraviolet-visible high-voltage corona recognition are mainly reflected in the dispersion system and the miniaturization of the overall structure is mainly reflected in the miniaturization of the input and output system, the miniaturization of the light source and the optical fiber connection between the probe and the instrument. The input and output system uses a touch screen to avoid the problem of large volume caused by the separation of the input and output system; the light source adopts an optical fiber light source to achieve miniaturization; the probe is selected to be placed outside the instrument and connected with the instrument by optical fiber to achieve long-distance measurement. From the perspective of the development of high-voltage corona recognition, the use of solid-state design array detectors can make high-voltage corona recognition a measurement and analysis device widely adapted to various fields. Technically, the use of optical fiber technology can make the configuration of high-voltage corona recognition flexible and portable; in design, modularization and optical fiber can make high-voltage corona recognition freely constructed; in terms of development concept, computer technology can make high-voltage corona recognition automatic, Intelligent.

Compact solid-state optical phased array beam scanners based on polymeric photonic integrated circuits

Optical phased array (OPA) devices are being actively investigated to develop compact solid-state beam scanners, which are essential in fields such as LiDAR, free-space optical links, biophotonics, etc. Based on the unique nature of perfluorinated polymers, we propose a polymer waveguide OPA with the advantages of low driving power and high optical throughput. Unlike silicon photonic OPAs, the polymer OPAs enable sustainable phase distribution control during beam scanning, which reduces the burden of beamforming. Moreover, by incorporating a tunable wavelength laser comprising a polymer waveguide Bragg reflector, two-dimensional beam scanning is demonstrated, which facilitates the development of laser-integrated polymeric OPA beam scanners.

Solid-state integrated micro-supercapacitor array construction with low-cost porous biochar

Solid-state micro-supercapacitor arrays made from porous biochar are integrated on flexible substrates by screen printing and writing, providing new insights into exploring low cost, eco-friendly, large scale integrated micro energy storage devices.

An Improved Calibration Method for Photonic Mixer Device Solid-State Array Lidars Based on Electrical Analog Delay.

As a typical application of indirect-time-of-flight (ToF) technology, photonic mixer device (PMD) solid-state array Lidar has gained rapid development in recent years. With the advantages of high resolution, frame rate and accuracy, the equipment is widely used in target recognition, simultaneous localization and mapping (SLAM), industrial inspection, etc. The PMD Lidar is vulnerable to several factors such as ambient light, temperature and the target feature. To eliminate the impact of such factors, a proper calibration is needed. However, the conventional calibration methods need to change several distances in large areas, which result in low efficiency and low accuracy. To address the problems, this paper presents an improved calibration method based on electrical analog delay. The method firstly eliminates the lens distortion using a self-adaptive interpolation algorithm, meanwhile it calibrates the grayscale image using an integral time simulating based method. Then, the grayscale image is used to estimate the parameters of ambient light compensation in depth calibration. Finally, by combining four types of compensation, the method effectively improves the performance of depth calibration. Through several experiments, the proposed method is more adaptive to multiscenes with targets of different reflectivities, which significantly improves the ranging accuracy and adaptability of PMD Lidar.

Controllable fabrication of solid state nanopores array by electron beam shrinking

Electron beam shrinking is a technique for manufacturing solid-state nanopores with direct visual feedback for better control. The electron beam in scanning electron microscopy (SEM) offers the high-resolution geometry information of nanostructure during the nanopore manufacturing processes. However, the mechanism of electron beam shrinkage is still unclear, which hinders the fabrication of solid-state nanopores array as well as their applications. In this study, Si3N4 nanopores were used as examples to explore the mechanism of electron beam shrinking. The morphology and composition characterization of the Si3N4 nanopores before and after shrinking revealed that the deposition of hydrocarbons dominates the shrinking process, accompanied by some decomposition of Si3N4. Based on this model, the controlled shrinking of nanopores was achieved, which were assembled into solid state nanopores array. The size of the nanopores can be accurately tuned by adjusting the electron beam accelerating voltage, beam current, and magnification. Under the optimal conditions, the smallest diameter of nanopore of 5.3 nm and the fastest shrinkage rate of 2.51 nm/s were obtained. Meanwhile, solid-state nanopores array, including an axisymmetric nanopore array structure, were also created for detecting translocated AuNPs-DNA through the shrunken nanopores. This study demonstrated a facile technique for fine control of the shape and size of nanopores with designed array patterns, which have great applications in producing nanogap electrodes, complex nanostructure, and surface modification or nanostructure repairing on different materials with desired geometries.