Photonic Properties Research Articles

Theranostic and Combined Approaches Exploiting Multifunctional Gold Nanoclusters in Tumoral Ecosystems: A Paradigm Shift in Precision Oncology.

Malignant tumors pose a significant threat to human life and well-being because of their rising occurrence and size. The current treatment methods and diagnostic techniques employed in clinical practice are inadequate for effectively treating tumors. Fluorescence, photothermal effects, radiosensitization, and biocompatibility are only a few instances of the unique photonic and physicochemical properties exhibited. Gold nanoclusters (AuNCs) are nanomaterials that possess modest dimensions, typically measuring approximately 3 nm, and are composed of a limited number of particles. AuNCs have three primary functions in practical applications: serving as imaging agents, drug transporters, and therapeutic agents. This article discusses nanosystems. The text emphasizes the promise of AuNCs for tumor theranostic and combination treatment while also acknowledging any existing limitations. Lastly, it is anticipated that the information presented here will serve as a valuable tool for researchers in this sector, resulting in novel perspectives and, ultimately, a wider adoption of AuNCs in pharmaceuticals. This study focuses on the expansion of diagnostic applications in cancer therapy by utilizing AuNC-based devices, made possible by the use of dynamic or passive tumor targeting techniques. The utilization of AuNCs has been thoroughly investigated for their prospective applicability as light-activated and radiation agents. Furthermore, they have been investigated as nanocarriers for transporting anticancer drugs. The medications can either bind to the closure receptor or be linked to the AuNCs through various techniques, showcasing their extensive potential for therapeutic applications.

Photonics of High-Entropy Polymers Revealing Molecular Dispersion via Polymer Mixing.

Blending multiple polymers together to form the so-called "high-entropy polymers (HEPs)" can generate the effects of molecular dispersion in addition to suppressing polymer phase separation. We embedded a semiconducting polymer (conjugated polymers, CPs) in an optically inert matrix composed of n polymer species and found that a molecule-level dispersion is attained in HEPs defined as n ≥ 5. In the regime of dilute CP concentrations, the photonic properties vary widely in the n = 1 matrices owing to diverse solubility parameters, but the distribution narrows with n, and the CP starts to exhibit behaviors of molecule-level dispersion at n ≥ 5, where the matrix polymers compete with each other to exert direct influences on the embedded CP. Specifically, for MEH-PPV, increasing n reduces the fluorescence redshift and spectral width from diminishing aggregation. For the rigid PFO molecules, increasing n creates a dilution effect facilitating formation of the low-energy planar β-phase. For the flexible regioregular P3HT-rr, HEPs offer well-dispersed amorphous chains highly susceptible to chain environments, thus influencing ηR's in the quasi-fixed amorphous-crystalline energy transfer landscape. The HEP effects continue for greater CP concentrations, consistent with the matrix dispersing behaviors in the dilute regime. This work demonstrates a molecular-level dispersion by HEPs, offering a method of molecular tailoring for polymer research and applications via simple mixing.

Photonic Properties of InGaN-Based Micro LEDs in the Cryogenic Temperature Regime

Photonic Properties of InGaN-Based Micro LEDs in the Cryogenic Temperature Regime

Stable Non-equilibrium Structures in Chiral Nematics under Microfluidic Flow.

Cholesteric liquid crystals (CLCs) are compelling responsive materials with applications in next-generation sensing, imaging, and display technologies. While electric fields and surface treatments have been used to manipulate the molecular organization and, subsequently, the optical properties of CLCs, their response to controlled fluid flow has remained largely unexplored. Here, we investigate the influence of microfluidic flow on the structure of thermotropic CLCs that can exhibit structural coloration. We demonstrate that the shear forces that arise from microfluidic flow align the helical axis of CLCs; alignment is a prerequisite for harnessing the promising photonic properties of CLCs. Moreover, we show that microfluidic flow can generate non-equilibrium structures exhibiting photonic band gaps that are inaccessible in the stationary cholesteric phase. Our findings have implications for the use of CLCs in applications involving flow processing such as additive manufacturing.

Photovoltaic response promoted via intramolecular charge transfer in triphenylpyridine core with small acceptors: A DFT/TD-DFT study

Currently, A−π−A configured molecules (TTP1-TTP6) were designed from the reference compound (TPPR) by modifying the terminal acceptors for photovoltaic materials. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) using the M06/6-311G(d,p) functional were employed to analyze the photonic and electronic properties of the newly designed derivatives. Various analyses; frontier molecular orbitals (FMOs), density of states (DOS), absorption spectra (λmax), transition density matrix (TDM), binding energy (Eb), hole-electron and open circuit voltage (Voc) were performed to explore the photovoltaic properties of triphenylpyridine based compounds. The structural modulation with acceptor moieties significantly tuned their HOMO and LUMO levels, resulting in reduced band gaps (2.833–3.037 eV). They also exhibited broader absorption spectra (λmax) ranging from 482.560 to 514.756 nm as compared to the reference compound (486.289 nm). Notably, TPP3 showed the good photovoltaic response as it displayed the least energy gap (2.833 eV) with lower binding energy (0.415 eV) and bathochromic shift (512.798 nm) in absorption spectra as compared to all other derivatives. Beside this, a comparative study with spiro-OMeTAD and P3HT standard hole transport materials illustrated that these materials can also be utilized as effective photovoltaic materials.

Active Photonic Glass for Hydrogen Generation.

Chirality is vital in many living species since it is responsible for structural iridescent coloration and plays a key role in light harvesting during natural photosynthesis. Developing photoactive materials with such chiral structures is a challenging but promising strategy for energy applications. Here, we describe a straightforward method to establish an active photonic glass obtained through the co-condensation oftetramethyl orthosilicate (TMOS) and titanium diisopropoxide bis(acetylacetonate) (TAA) dissolved in a liquid crystal formed from cellulose nanocrystalline (CNC). The inorganic glass maintains a long range of chiral nematic ordering, displaying iridescent colors characterized by a Bragg peak reflection. The reflected wavelengths are tuned all over the UV-visible range, demonstrating that the replica of the chiral nematic structure generates photonic properties. Incorporation of gold nanoparticles (Au NPs) into the films is further performed by impregnation/chemical reduction. We show that the charge carrier density and photocatalytic H2 generation were amplified when the photonic band gap edges matched the absorbance of the TiO2 and localized surface plasmon resonance (LSPR) of AuNPs. This photocatalytic glass with chiral nematic ordering and a tunable photonic bandgap paves the way for the development of metamaterials with new applications, such as asymmetric photocatalysis.

Tailored Growth of Transition Metal Dichalcogenides' Monolayers by Chemical Vapor Deposition.

Here, results on the tailored growth of monolayers (MLs) of transition metal dichalcogenides (TMDs) are presented using chemical vapor deposition (CVD) techniques. To enable reproducible growth, the flow of chalcogen precursors is controlled by Knudsen cells providing an advantage in comparison to the commonly used open crucible techniques. It is demonstrated that TMD MLs can be grown by CVD on large scale with structural, and therefore electronic, photonic and optoelectronic properties similar to TMD MLs are obtained by exfoliating bulk crystals. It is shown that besides the growth of the "standard" TMD MLs also the growth of MLs that are not available by the exfoliation is possible including examples like lateral TMD1-TMD2 ML heterostructures and Janus TMDs. Moreover, the CVD technique enables the growth of TMD MLs on various 3D substrates on large scale and with high quality. The intrinsic properties of the grown MLs are analyzed by complementary microscopy and spectroscopy techniques down to the nanoscale with a particular focus on the influence of structural defects. Their functional properties are studied in devices including field-effect transistors, photodetectors, wave guides and excitonic diodes. Finally, an outlook of the developed methodology in both applied and fundamental research is given.

Enhancing Optical Microscopy with Quantum Entanglement

Drawing on the unique properties of entangled photons, quantum approaches can overcome the limitations of classical methods, enhance spatial resolution and reduce stray light and shot noise.

Nonlinear LiNbO3 topological Tamm interface state photonic crystal with static visible and intelligent laser protection

The rapid advancement of high-energy laser and LiDAR technologies imposes heightened demands on intelligent laser protection windows. Traditional laser protection devices often face difficulty in simultaneously achieving high absorption of low-energy laser and high reflection of high-energy laser. Herein, we investigate the efficacy of one-dimensional nonlinear LiNbO3 topological Tamm interface state photonic crystal for static visible and intelligent laser protection applications. The photonic crystal's intelligent laser protection property arises from the amplification of nonlinear effects facilitated by the intense electric field localization surrounding the LiNbO3 interface. At 1064 nm laser energy levels below 18.29 mJ/cm2, the protection window exhibits up to 87.03% absorption. When the laser energy increased to 83.84 mJ/cm2, the reflectance reaches 88.07% attributed to the unsatisfied amplitude matching condition caused by the LiNbO3 nonlinear effect, thereby achieving successful intelligent laser protection. Furthermore, the fabricated sample demonstrates a maximum transmittance of 47.51% in the visible wavelength range. This research provides novel insights into the development of multifunctional advanced optical elements.

Integrated convolutional kernel based on two-dimensional photonic crystals.

Optical neural networks (ONNs) exhibit significant potential for accelerating artificial intelligence task processing due to their low latency, high bandwidth, and parallel processing capabilities. Photonic crystals (PhCs) are extensively utilized in integrated optoelectronics because of their unique photonic bandgap properties and precise control of light waves. In this study, we propose an optical reconfigurable convolutional kernel based on PhCs. This kernel can perform convolutional operations on weights by constructing a PhC weight bank. The convolutional kernel demonstrates exceptional performance within the developed optical convolutional neural network framework, successfully realizing various image edge processing tasks. It achieves blind recognition accuracies of 97.81% for the MNIST dataset and 80.31% for the Fashion-MNIST dataset. This study not only demonstrates the feasibility of constructing optical neural networks based on PhCs but to our knowledge, also offers new avenues for the future development of optical computing.

Dibenzoquinone Cyclopentadithiophene Diradicaloids Show Optical Transitions of Different Spin States and Anomalous Near‐Infrared Emission

AbstractWe have prepared a series of bis(semiquinone) compounds with dithiophene bridges of different length that evolve from closed‐shell (smaller compound) to full diradical (longer compound) for which the narrow singlet‐triplet energy gap allows the triplet population at 298 K. The medium size system has a variety of photonic properties with absorptions and emission in the optical near‐infrared region mediated by a unique case of anti‐Kasha emission. A whole set of optical absorption/emission and vibrational steady state spectroscopies as well as picosecond transient absorption spectroscopy, all complemented with spectroelectrochemistry and theoretical calculations, is presented.

Optical Performance of Quantum Dots and Their Applications in Biomedical Imaging

Quantum dots are nanomaterials which have attracted significant focus over the past few years because of their singular optical features. They have shown great potential in the field of bioimaging. This study delves into the photonic properties of quantum dots which include good luminescence stability and broad excitation spectra. Besides, the emission wavelength can be precisely controlled. These properties make them an excellent choice for bio-imaging. The usage of quantum dots in live organism imaging, such as pinpointing cell boundaries, tracking intracellular molecular dynamics, and early disease diagnosis, indicate the immense potential of quantum dots in biomedical realm. Through modifications on the surface of quantum dots, targeted imaging can be realized, which greatly improves the specificity and sensitivity of imaging. Nonetheless, the biosafety and long-term in vivo behavior of quantum dots still need to be further investigated. Overall, the light-based attributes of quantum dots have brought breakthroughs in bio-imaging technology. In addiiton, it would foretell a bright future for quantum dots in the biomedical field.

Long‐Term Monitoring of ApoE4 within Aqueous Humor Using Intraocular Lenses Containing Target‐Responsive Inverse Opal Hydrogel

Neurodegenerative diseases, including Alzheimer's disease (AD), pose significant challenges to global healthcare because of their irreversible postsymptomatic progression. Conventional radiographic techniques have limitations in early detection, owing to the time lapse between symptom recognition by individuals and precise inspection using medical instruments. Current research explores ophthalmic approaches to address this gap, investigating the physiological link between ocular health and brain diseases. Intraocular lenses (IOLs), widely used in cataract and refractive surgeries, provide a safe and minimally invasive platform for the continuous monitoring of neurodegenerative disease biomarkers, including those associated with AD. By integrating biomolecule‐responsive sensors with IOLs, it becomes feasible to achieve early diagnosis and long‐term, noninvasive monitoring postimplantation. Herein, a fluorescently labeled inverse opal hydrogel (FIOH) is merged with IOLs for ApoE4 detection, a key risk factor for AD. The permeability and inherent photonic properties of FIOH facilitate the cumulative enhancement of the fluorescence signal. In a simulation of the aqueous humor circulation, the detection limit for ApoE4 is determined to be 0.1 nM. Therefore, FIOH‐integrated IOLs hold promise not only for early detection but also for providing a reliable platform for the continuous, noninvasive monitoring of neurodegenerative diseases after the initial, minimally invasive implantation.

Diatoms in Focus: Chemically Doped Biosilica for Customized Nanomaterials.

Diatoms are photosynthetic microalgae widely diffused around the globe and well adapted to thrive in diverse environments. Their success is closely related to the nanostructured biosilica shell (frustule) that serves as exoskeleton. Said structures have attracted great attention, thanks to their hierarchically ordered network of micro- and nanopores. Frustules display high specific surface, mechanical resistance and photonic properties, useful for the design of functional and complex materials, with applications including sensing, biomedicine, optoelectronics and energy storage and conversion. Current technology allows to alter the chemical composition of extracted frustules with a diverse array of elements, via chemical and biochemical strategies, without compromising their valuable morphology. We started our research on diatoms from the viewpoint of material scientists, envisaging the possibilities of these nanostructured silica shells as a general platform to obtain functional materials for several applications via chemical functionalization. Our first paper in the field was published in ChemPlusChem ten years ago. Ten years later, in this Perspective, we gather the most recent and relevant functional materials derived from diatom biosilica to show the growth and diversification that this field is currently experiencing, and the key role it will play in the near future.

Gated InAs quantum dots embedded in surface acoustic wave cavities for low-noise optomechanics

Self-assembled InAs quantum dots (QDs) are promising optomechanical elements due to their excellent photonic properties and sensitivity to local strain fields. Microwave-frequency modulation of photons scattered from these efficient quantum emitters has been recently demonstrated using surface acoustic wave (SAW) cavities. However, for optimal performance, a gate structure is required to deterministically control the charge state and reduce the charge noise of the QDs. Here, we integrate gated QDs and SAW cavities using molecular beam epitaxy and nanofabrication. We demonstrate that with careful design of the substrate layer structure, integration of the two systems can be accomplished while retaining the optimal performance of each subsystem. These results mark a critical step toward efficient and low-noise optomechanical systems that truly leverage the excellent properties of semiconductor QDs.

A basic study on sound insulation characteristics of Triply Periodic Minimal Surface by using the finite element method

Triply periodic minimal surfaces (TPMS) have garnered attention in the field of natural science. For example, these structures are observed in insect wing scales, where their intricate periodic structures create structural colors via the reflection and interference of certain wavelengths of light. The objective of this study is to utilize the acoustic analogy of such photonic properties for sound insulation. In a previous report, it was found that the bandgap of G-surface, which is one of TPMS, enabled us to insulate sound effectively at specific frequencies. Furthermore, it was suggested that sound insulation performance can be improved by compressing the structure along the incident direction while maintaining its thickness. In this paper, we focus on the P-surface, which is a typical TPMS other than the G-surface. The sound insulation properties were calculated by numerical analysis and compared with those of the G-surface. As a result, it is found that P- and G-surfaces are effective structures for different frequency bands. In addition, compression of the P-surface along the incident direction in the same manner as in the previous study improves the sound insulation performance without increasing the thickness, as well as G-surface.

Information and mathematical model of quantum communication channel state control processes

The most protected and stable communication systems today are quantum channels of information transmission and processing. Thanks to the unique properties of photons as information elements, it becomes possible to monitor and analyze the state of information flows in communication or information transmission channels. Physical attributes such as spin, polarization, radiation frequency, phase synchronization, and the quantum entanglement effect can be tracked and interpreted online to improve the quality and reliability of information in computer systems. In order to effectively use information in support or decision support systems, it is necessary to carefully formalize the processes and indicators of quantum systems for the creation of information processing and transmission, for which information and mathematical models should be created that describe the state of the quantum communication channel (QCC).The information model should allow the convolution of the information space. The mathematical model must prove the processes of tracking the states of quantum information and provide a description of the phase state of indicators of the quantum environment. A lock in a closed space with established cause-and-effect relationships is equal to a system of clear logic.The authors summarize the experience of developing and implementing the method of simulated dynamic modeling of events in an abstract communication channel, which allows formalizing and classifying cause-and-effect relationships of quantum carriers in the analyzed channels. It is proposed to use a unified neural network for the organization of SPPR in quantum-mechanical information transmission systems. Such a network could provide an automatic intelligent system state analysis mode. Such an analysis makes it possible to classify the aggregates of current system parameters to the level of diagnostics of the state of information flows and conclusions based on such diagnostics with the support of decision-making about the quality and reliability of the transmitted information. Such a system, working in OLAP (Online analytical processing) mode, could automatically manage the process of generation and transmission of information, reacting without human intervention to emerging critical errors or attempts at unauthorized system hacking. The observer effect leads to the fact that an attempt to measure the state of a photon inevitably causes an almost instantaneous change in this state. Attempting to parallelize a photon has the same consequences. This cannot be unnoticeable during further authorized acceptance of information. The analyzed quantum communication channel (QCM) consists of a set of technological elements distributed in space. The channel works in its own time, which is formed by clock pulses and creates a flow of information.

Synthesis of Doped g‐C3N4 Photonic Crystals for Enhanced Light‐Driven Hydrogen Production from Catalytic Water‐Splitting

Dopants are frequently used to improve graphitic carbon nitride (gCN) photoactivity. As a doping source, phosphomolybdic acid (PMA) can activate doping sites inside the gCN lattice, resulting in 2D Mo:P‐gCN porous material. However, the gradual loading of the PMA fraction has no systematic improvement in the Mo:P‐gCN photoactivity. For improving the optoelectronic properties of Mo:P‐gCN, its textural geometry is a controllable parameter that can provide enhanced photonic properties, achievable by shaping its morphology through a crystalline template structure, namely, photonic crystals (PCs). Herein, a doped PC material is made of Mo:P‐gCN and PCs and labeled as Mo:P‐gCN/PCs. The impact of PCs is highlighted in the structural, electronic, and optical performances of Mo:P‐gCN. A well‐defined 3D crystalline network is evidenced by microscopic measurements (scanning electron microscopy, AFM, focused ion beam). Mo:P‐gCN/PCs shows a hydrogen production rate (750 μmol g−1 h−1) one time higher than Mo:P‐gCN and 6 times higher than pure gCN. The synthesis strategy proposed in this work leads simultaneously to the Mo:P codoping effect provided by PMA and the slow photon effect due to the PC structure, offering a novel strategy to improve the gCN photoactivity by simultaneously applying polyoxometalates as modifiers and polystyrene opals as templates.

Using both faces of polar semiconductor wafers for functional devices

Unlike non-polar semiconductors such as silicon, the broken inversion symmetry of the wide-bandgap semiconductor gallium nitride (GaN) leads to a large electronic polarization along a unique crystal axis1. This makes the two surfaces of the semiconductor wafer perpendicular to the polar axis substantially different in their physical and chemical properties2. In the past three decades, the cation (gallium) face of GaN has been used for photonic devices such as light-emitting diodes (LEDs) and lasers3–5. Although the cation face has also been predominantly used for electronic devices, the anion (nitrogen) face has recently shown promise for high-electron-mobility transistors (HEMTs) owing to favourable polarization discontinuities6. In this work, we introduce dualtronics, showing that it is possible to make photonic devices on the cation face and electronic devices on the anion face of the same semiconductor wafer. This opens the possibility for making use of both faces of polar semiconductors in a single structure, in which electronic, photonic and acoustic properties can be implemented on opposite faces of the same wafer, markedly enhancing the functional capabilities of this revolutionary semiconductor family.

Astrophotonics: recent and future developments

Astrophotonics is a burgeoning field that lies at the interface of photonics and modern astronomical instrumentation. Here we provide a pedagogical review of basic photonic functions that enable modern instruments, and give an overview of recent and future applications. Traditionally, optical fibres have been used in innovative ways to vastly increase the multiplex advantage of an astronomical instrument, e.g. the ability to observe hundreds or thousands of stars simultaneously. But modern instruments are using many new photonic functions, some emerging from the telecom industry, and others specific to the demands of adaptive optics systems on modern telescopes. As telescopes continue to increase in size, we look to a future where instruments exploit the properties of individual photons. In particular, we envisage telescopes and interferometers that build on international developments in quantum networks, the so-called quantum internet. With the aid of entangled photons and quantum logic gates, the new infrastructures seek to preserve the photonic state and timing of individual photons over a coherent network.