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Because copper phthalocyanine (CuPc) has significant uses in industrial devices and pigments, it is a subject of great interest in basic scientific research. Studying and adjusting its photoelectric qualities, in particular, has drawn much attention. In this work, in situ high-pressure experiments were used to investigate in detail the vibrational and optical properties of ground-state β-CuPc up to 13 GPa. Both micro-Raman and ultraviolet and visible light (UV–vis) absorption measurements revealed a phase transition occurring around 3 GPa. Notably, the macrocycle breathing vibration was found to have a remarkable characteristic of first weakening and then strengthening in response to this pressure-induced phase transition. The UV–vis absorption data revealed that the bandgaps corresponding to the two absorption edges decrease gradually with increasing pressure, with one edge disappearing entirely above 11 GPa. Furthermore, the blue β-CuPc can be adjusted to dark green at 10 GPa and ultimately entirely black due to the merging of its absorption bands and redshifts at high pressure. This work improves our understanding of CuPc's intrinsic characteristics under harsh settings and manipulates its color effectively. [ABSTRACT FROM AUTHOR]

Nonpolar (100), polar (002), semipolar (101), and nonpolar (110) preferred oriented ZnO films were synthesized by regulated growth using the chemical bath deposition method. The crystallinity, surface morphology, and optical properties of ZnO films with different preferred orientations after annealing in different atmospheres were systematically investigated. The experimental results show an increase in crystallinity and a decrease in surface roughness of the films after annealing; in particular, the optical transmittance of semipolar (101) preferred oriented ZnO films was significantly higher than that of the other samples. XPS and PL spectra confirmed that annealing in argon effectively increased donor defects, whereas annealing in oxygen and ozone reduced donor defects in the films, and that ozone annealing was best suited to enhance acceptor defects in nonpolar (110) preferred oriented ZnO films. Argon annealing is the best for the enhancement of donor defects in polar (002) preferred oriented ZnO films. This work achieves modulation of optical properties and defects of ZnO films by annealing in different atmospheres, which provides new ideas for the application of ZnO materials. [ABSTRACT FROM AUTHOR]

The emergence of many efficient optical field modulation methods and planar optical devices is attributed to the continuous research of geometric phase. Nevertheless, conjugate symmetry of the geometric phase limits the multiplexing of metasurfaces. To overcome this limitation, integrating the propagation phase and the geometric phase to achieve self-decouped metasurfaces can effectively double channel capacity. Herein, a more in-depth derivation of Jones matrices is conducted, leveraging two degrees of freedom offered by the propagation phase and the geometric phase. This approach enables complete modulation in circular polarization channels. By designing the phase difference between a fast axis and a slow axis, energy allocation between different channels can be controlled. It means independent complex amplitude modulation is achieved. On this basis, the geometric phase is introduced to realize tri-channel multiplexing metasurfaces. To verify the feasibility of this method, two metasurfaces are designed, including a bifocal metasurface with adjustable energy allocation and a tri-channel multiplexing metasurface. The proposed multifunctional metasurface offers new insights into wavefront multiplexing for communication systems. [ABSTRACT FROM AUTHOR]

VO2-based thermochromic coatings have gained much attention in temperature-adaptive smart windows, and constructing multilayer film structures is the main way to obtain high thermochromic performances. Based on the self-developed objective-orientated automatic optimization code, the present research realized customized designs of thermochromic multilayer coatings composed of VO2, TiO2, and SiO2 from the objectives of visible luminance (Tlum) and solar light modulation (ΔTsol). The TiO2/VO2/s, VO2/TiO2/s, TiO2/VO2/TiO2/s, and SiO2/TiO2/VO2/TiO2/s (s denotes substrate) multilayer film systems were then prepared by magnetron sputtering and vacuum controllable heating, with their structures, insulator-metallic transition, and thermochromic properties being carefully studied. The result showed that the best trade-off between high Tlum and high ΔTsol was achieved for these film assemblies, and solar light modulation was mainly limited at the near-IR wavelength region of the solar spectrum, with the difference between cool- and hot-state Tlum being greatly reduced. In the case of the four-layer SiO2/TiO2/VO2/TiO2/s, very high average Tlum (60%) and high ΔTsol (14%) were obtained. A 100 × 100 mm2 of the SiO2/TiO2/VO2/TiO2/s was also prepared, and it showed an obvious temperature adjustment, and the service life can last for 14 years under normal weather conditions. Not limited to the prepared multilayer film systems, the methodology used here is also suitable for the fast development of other multilayer film systems. [ABSTRACT FROM AUTHOR]

With the in-depth study of open optical systems, the topological phases of non-Hermitian metasurfaces have attracted increasing attention due to their topological protection properties. Here, in this paper, a tunable non-Hermitian metasurface with bidirectional anisotropism is proposed. By incorporating the phase change material vanadium dioxide (VO2) into the metasurface, two topological exceptional points (EPs) appear in the system by adjusting the conductivity of VO2 and chiral responses appear at both EPs. This research shows that the conductivity significantly affects the reflection of the metasurface, and the zero-reflection points correspond to the EPs of the non-Hermitian system. Further results prove that circling around EPs leads to a 2π phase change, which is topologically protected and independent of the encirclement path. Therefore, this study employs an active control approach to realize two topological EPs. Through comprehensive investigations into the topological properties and chiral performance at EPs, we elucidate the mechanism for the chirality generation in non-Hermitian metasurfaces, which offers feasible solutions for the development of chiral topological devices and light transmission and modulation in future applications. [ABSTRACT FROM AUTHOR]

The discovery of strontium niobate (SNO) as a potentially new transparent electrode has generated much interest due to its implications in various optoelectronic devices. Pristine SNO exhibits exceptionally low resistivity (∼10−4 Ω cm) at room temperature. However, this low resistivity occurs due to large number of carrier concentration in the system, which significantly affects its optical transparency (∼40%) in the visible range and hinders its practical applications as a transparent electrode. Here, we show that modulating the growth kinetics via oxygen manipulation is a feasible approach to achieve the desired optoelectronic properties. In particular, epitaxial (001) SNO thin films are grown on (001) lanthanum aluminate by pulsed laser deposition at different oxygen partial pressures and are shown to improve the optical transparency from 40% to 72% (λ = 550 nm) at a marginal cost of electrical resistivity from 2.8 to 8.1 × 10−4 Ω cm. These changes are directly linked with the multi-valence Nb-states, as evidenced by x-ray photoelectron spectroscopy. Furthermore, the defect-engineered SNO films exhibit multiple electronic phases that include pure metallic, coexisting metal-semiconducting-like, and pure semiconducting-like phases as evidenced by low-temperature electrical transport measurements. The intriguing metal-semiconducting coexisting phase is thoroughly analyzed using both perpendicular and angle-dependent magnetoresistance measurements, further supported by a density functional theory-based first-principles study and the observed feature is explained by the quantum correction to the conductivity. Overall, this study shows an exciting avenue for altering the optical and transport properties of SNO epitaxial thin films for their practical use as a next-generation transparent electrode. [ABSTRACT FROM AUTHOR]

The development of a simple and efficient method for preparing porous tungsten trioxide (WO3) electrochromic films using structure-directing agents is highly urgent for their industrialization. To this end, this work presents an efficient approach using rapid co-pyrolysis of polyethylene glycol 400 (PEG-400) and ammonium metatungstate (AMT) to produce mesoporous WO3 thin films. The findings indicate that the concentration of PEG influences both the wettability of the precursor solution on the FTO substrate and the state of the PEG micelle solution, ultimately leading to WO3 films with diverse morphologies after the co-pyrolysis of AMT and PEG. The porous structure significantly enhances hydrogen ion intercalation/deintercalation, and thus improves electrochromic properties. The optimized electrochromic films demonstrate a 54.5% optical modulation range at 633 nm, fast switching times (2.8 s for coloration and 1.5 s for bleaching), and a coloration efficiency of 83.2 cm2 C⁻1. In pursuit of broader optical modulation capabilities, we further innovated by developing a multilayer porous film strategy, enabling precise control over thickness through repeated spin-coating/heating cycles. Remarkably, a three-layer configuration achieved an extraordinary optical modulation of up to 87.2%, ranking among the best performances reported in the electrochromic field. This novel methodology paves the way for expedited manufacturing of porous amorphous metal oxide films and positions the enhanced WO3 film as a highly promising candidate for advanced electrochromic technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] • An optoelectronic spiking neuron is developed. • The gate-modulated PDVT-10 channel was combined with a volatile threshold switching memristor. • The device achieves optoelectronic performance through resistance-matching mechanism. • The neuron alters its spiking behavior in a manner resembling that of a retina. • The artificial neuron accurately replicates neuronal signal transmission in a biologically manner. The human perception and learning heavily rely on the visual system, where the retina plays a vital role in preprocessing visual information. Developing neuromorphic vision hardware is based on imitating the neurobiological functions of the retina. In this work, an optoelectronic neuron is developed by combining a gate-modulated PDVT-10 channel with a volatile threshold switching memristor, enabling the achievement of optoelectronic performance through a resistance-matching mechanism. The optoelectronic spiking neuron exhibits the ability to alter its spiking behavior in a manner resembling that of a retina. Incorporating electrical and optical modulation, the artificial neuron accurately replicates neuronal signal transmission in a biologically manner. Moreover, it demonstrates inhibition of neuronal firing during darkness and activation upon exposure to light. Finally, the evaluation of a perceptron spiking neural network utilizing these leaky integrate-and-fire neurons is conducted through simulation to assess its capability in classifying image recognition algorithms. This research offers a hopeful direction for the development of easily expandable and hierarchically structured spiking electronics, broadening the range of potential applications in biomimetic vision within the emerging field of neuromorphic hardware. [ABSTRACT FROM AUTHOR]

[Display omitted] • Delves into the design and synthesis of Nb 2 O 5 -TiO 2 bilayer thin films via hydrothermal method. • Intricate analysis of dual-band electrochromic energy storage through Nb 2 O 5 -TiO 2 bilayer nanoarchitectonics. • Investigate the influence of TiO 2 varying annealing temperature on overall electrochemical performance. • The objective of study is to regulate light and thermal dynamics while exhibiting superior charge storage. • The development of large-scale device boasting exceptional electrochromic energy storage characteristics. This paper introduces a proof of concept for a dual-band electrochromic (EC) device to modulate solar light transmission across visible and near-infrared regions selectively. EC materials based on ion insertion/extraction mechanisms also present the possibility for energy storage, widening its functionality to the supercapacitor platform. The bi-functional performance of dual-band radiation control and energy storage was achieved by exploiting two earth-abundant metal oxides that could absorb two different spectral regions when electrochemically charged. The bilayer structure was prepared using a one-step hydrothermal method, which produced Nb 2 O 5 -TiO 2 bilayer on fluorine-doped tin oxide (FTO) conducting glass substrates. The nano-dimensions of the active materials endorse the development of high-transparency thin film under open circuit conditions. The variations in the TiO 2 annealing temperature influence the crystallinity and surface morphology of the thin films, which influence the performance of dual-band EC energy storage. The well-optimized NT-500 sample facilitated exclusive electron-charge transport, producing excellent electrochemical performance in dual-band EC and energy storage. A large optical modulation of 80.4 % and 89.8 % at 600 nm and 800 nm (near-infrared) was achieved with an enhanced areal capacitance of 88.1 mF/cm2 and excellent cycling stability after continuous coloring/bleaching cycles for 18,000 s. This paper presents a prototype bi-functional device based on NT-500, which showed independent control and modulation of visible and near-infrared transmittance. Notably, the device retained excellent energy storage performance alongside its advanced optical functionalities. This bilayer nanostructure capitalizes on the inherent electrochemical properties of both materials and introduces novel features that can potentially revolutionize the platform of EC-energy storage. [ABSTRACT FROM AUTHOR]

Optical resolution photoacoustic imaging of uneven samples without z-scanning is transformative for the fast analysis and diagnosis of diseases. However, current approaches to elongate the depth of field (DOF) typically imply cumbersome postprocessing procedures, bulky optical element ensembles, or substantial excitation beam side lobes. Metasurface technology allows for the phase modulation of light and the miniaturization of imaging systems to wavelength-size thickness. Here, we propose a metalens composed of submicrometer-thick titanium oxide nanopillars, which generates an elongated beam of diffraction-limited diameter with an aspect ratio of 286 and a uniform intensity throughout the DOF. The metalens enhances visualization of phantom samples with tilted surfaces compared to conventional lenses. Moreover, the volumetric imaging of neuromelanin is facilitated for depths of up to 500 micrometers within the human midbrain and forebrain organoids that are 3D biological models of human brain regions. This approach provides a miniaturized platform for neurodegenerative disease diagnosis and drug discovery. [ABSTRACT FROM AUTHOR]

We proposed and investigated a refinement of technology for obtaining Mg-doped LiNbO3 (LN) crystals by co-doping it with B. LN:Mg (5.0 mol%) is now the most widely used material based on bulk lithium niobate. It is suitable for light modulation and transformation. We found that non-metal boron decreases threshold concentrations of the target dopant in many ways. In addition, we earlier determined that the method of boron introduction into the LN charge strongly affects the LN:B crystal structure. So we investigated the point structural defects of two series of LN:Mg:B crystals obtained by different doping methods, in which the stage of dopant introduction was different. We investigated the features of boron cation localization in LN:Mg:B single crystals. We conducted the study using XRD (X-ray diffraction) analysis. We have confirmed that the homogeneous doping method introduces an additional defect (MgV) into the structure of LN:Mg:B single crystals. Vacancies in niobium positions (VNb) are formed as a compensator for the excess positive charge of point structural defects. According to model calculations, boron is localized in most cases in the tetrahedron face common with the vacant niobium octahedron from the first layer (VNbIO6). The energy of the Coulomb interaction is minimal in the LN:Mg:B crystal (2.57 mol% MgO and 0.42 × 10−4 wt% B in the crystal); it was obtained using the solid-phase doping technology. The solid-phase doping technology is better suited for obtaining boron-containing crystals with properties characteristic of double-doped crystals (LN:Mg:B). [ABSTRACT FROM AUTHOR]

Electrochromic (EC) smart windows can block the sun-light and solar radiation, and reduce energy consumption, contributing to the objective of carbon neutrality. EC materials play an essential role in EC smart windows. However, bimetallic oxides or hydroxides currently cannot meet a large optical modulation and neutral coloration. Herein, we report a new Ni-based bimetallic hydroxide with improved EC properties. By using a simple solvothermal process, uniform Ni 4 W 6 O 21 (OH) 2 ·4H 2 O films were directly grown on fluorine-doped tin oxide (FTO) conductive glasses. The morphologies of the as-grown Ni 4 W 6 O 21 (OH) 2 ·4H 2 O films are affected by the concentration of the precursor solution. When the concentration of the nickel source is 15 mmol L−1, the film shows rice-like nanostructures. Moreover, the film not only exhibits a large optical modulation of 80.5 % and a high coloration efficiency of 256.8 cm2 C−1, but also shows a neutral coloration from transparent to dark brown. The improved EC properties of the as-grown Ni 4 W 6 O 21 (OH) 2 ·4H 2 O film is associated with its rice-like nanostructures, which can create more reactive sites. Meanwhile, an EC device was constructed using the Ni 4 W 6 O 21 (OH) 2 ·4H 2 O film and its EC properties were investigated. The results expand the family of anodically coloring Ni-based EC materials and demonstrate the potential application of Ni-W bimetallic hydroxides in high-performance EC smart windows. [Display omitted] • Ni 4 W 6 O 21 (OH) 2 ·4H 2 O films with rice-like and porous nanostructures were directly grown on fluorine-doped tin oxide glasses. • Ni 4 W 6 O 21 (OH) 2 ·4H 2 O films only show anodically coloring electrochromism. • The transmittance of the bleached film is 90.1 %, resulting in a large optical modulation of 80.5 %. [ABSTRACT FROM AUTHOR]

AbstractIntensity modulation plays a crucial role in developing the indirect Time of Flight (i-ToF) LiDAR because it enables the system to precisely measure distances, enhance accuracy and resolution, reduce noise, and avoid environmental interference. This work observes the modulation parameters—such as bias current on the laser diode, modulation frequency, and amplitude of modulation—that impact LiDAR’s performance. By combining such parameters, the average optical power transmitted by the LiDAR system is investigated by an optical power meter at a distance of up to 55 meters. The results demonstrate that changing the bias current increases the average optical power from 14.14 mW at 60 mA, 29.53 mW at 100 mA, and 40.6 mW at 130 mA. However, adjusting modulation frequencies of 2 MHz and 10 MHz and the modulation amplitudes of 1000 mV and 1500 mV had minimal influence on the average optical power. The optimal combination of 60 mA bias current, 2 MHz modulation frequency, and 1500 mV amplitude modulation results in stable optical power, high accuracy, and operational safety for i-ToF LiDAR. This analysis recommends that a combination of modulation parameters should be compromised between increasing optical power to achieve a good signal-to-noise ratio (SNR) and safe operation. [ABSTRACT FROM AUTHOR]

Achieving highly tailored control over both the spatial and temporal evolution of light's orbital angular momentum (OAM) on ultrafast timescales remains a critical challenge in photonics. Here, we introduce a method to modulate the OAM of light on a femtosecond scale by engineering a space-time coupling in ultrashort pulses. By linking azimuthal position with time, we implement an azimuthally varying Fourier transformation to dynamically alter light's spatial distribution in a fixed transverse plane. Our experiments demonstrate self-torqued wave packets that exhibit spiraling motions and rapid temporal OAM changes down to a few femtoseconds. We further extend this concept to generate angularly self-accelerating wave packets that adjust their OAM by redistributing their energy density across their spectral bandwidth, without external forces. The ability to tune the spatial-temporal properties of light on demand opens the possibility for exploring ultrafast light dynamics at fundamental timescales, with far-reaching implications for ultrafast spectroscopy, nano-and microstructure manipulation, condensed matter physics, and other related areas. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) birefringent crystals have important applications in polarizers, optical isolators and optical information processing. Crystals with large birefringence can enhance the modulation ability of light and realize the miniaturization of devices. However, the birefringence of cyanurates is often limited by the large dihedral angles between anionic groups. In this work, a chiral-driven approach is proposed for the first time to construct cyanurates with large birefringence. We combined racemic or chiral α-methylbenzylamine (α-MBA) molecules with a π-conjugated cyanurate group (CY), which led to the isolation of three organic hybrid cyanurates with wide band gaps >5.10 eV, namely, rac-α-MBACY, R-α-MBACY, and S-α-MBACY. Notably, the presence of chirality leads to a significant reduction of the dihedral angle between the α-MBA cation and (H2C3N3O3)− anion and a threefold increase in birefringence from 0.113@546 nm to 0.344@546 nm and 0.338@546 nm. The birefringence values of R-α-MBACY and S-α-MBACY exceed those of most of the cyanurates and commercial crystals, indicating their potential as UV birefringent crystals. This work provides new insights into the design and syntheses of UV birefringent materials. [ABSTRACT FROM AUTHOR]

BaTiO3 (BTO) thin films were deposited on LaNiO3 (LNO)/SiO2/Si substrates by magnetron sputtering, and the LNO thin film was deposited as a bottom electrode and a buffer layer. The bipolar resistive switching (RS) behaviors have been observed in the Al/BTO/LNO devices, and the effect of illumination conditions on the RS behavior was investigated. The set voltage was effectively reduced by the photogenerated carrier, and a greatly improved OFF/ON resistance ratio of ∼120 was achieved under high light conditions. The Al/BTO/LNO devices showed good endurance and retention performance. The conduction mechanisms of the Al/BTO/LNO devices have been discussed based on the migration of defects and photogenerated carriers. These results facilitated a deeper study of BTO‐based multifunctional storage devices and demonstrated the tunable photoresponse characteristic. [ABSTRACT FROM AUTHOR]

An electrochromic supercapacitor device (ESD) is an advanced energy storage device that combines the energy storage capability of a supercapacitor with the optical modulation properties of electrochromic materials. The electrode materials used to construct an ESD need to have both rich color variations and energy storage properties. Recent advances in ESDs have focused on the preparation of novel electrochromic supercapacitor electrode materials and improving their energy storage capacity, cycling stability, and electrochromic performance. In this review, the research significance and application value of ESDs are discussed. The device structure and working principle of electrochromic devices and supercapacitors are analyzed in detail. The research progress of inorganic materials, organic materials, and inorganic/organic nanocomposite materials used for the construction of ESDs is discussed. The advantages and disadvantages of various types of materials in ESD applications are summarized. The preparation and application of ESD electrode materials in recent years are reviewed in detail. Importantly, the challenges existing in the current research and recommendations for future perspectives are suggested. This review will provide a useful reference for researchers in the field of ESD electrode material preparation and application. [ABSTRACT FROM AUTHOR]

Electrochromic devices (ECDs) are devices that change their optical properties in response to a low applied voltage. These devices typically consist of an electrochromic layer, a transparent conducting substrate, and an electrolyte. The advancement in solid-state ECDs has been driven by the need for improved durability, optical performance, and energy efficiency. In this study, we investigate varying the temperature to the casting solution for polymethylmethacrylate (PMMA)-based electrolytes for solid-state ECDs with a structure of glass/ITO/WO3/PMMA electrolyte/ITO/glass. The electrochromic layer, composed of WO3, was deposited using the sol-gel method, while the electrolyte, comprising lithium perchlorate (LiClO4) in propylene carbonate (PC) with PMMA, was prepared via solution casting. Various electrolyte samples were heated at different temperatures of 25, 40, 60, 80, and 100 °C to analyze the impact on the devices' performance. Our findings indicate that the devices with electrolytes at 25 °C exhibited superior anodic and cathodic diffusion. An increase in heating temperature corresponded with an increase in switching time. Notably, the sample heated at higher temperatures (60, 80, and 100 °C) demonstrated exceptional cycle stability. Nevertheless, samples with higher temperatures displayed a decrease in optical modulation. Additionally, the 100 °C sample exhibited the highest coloration efficiency compared to other samples at lower temperatures. This research highlights the potential of varying the temperature of solution casting on PMMA-based electrolytes in optimizing the performance of solid-state ECDs, particularly regarding coloration efficiency and durability. [ABSTRACT FROM AUTHOR]

Exploring structural phase transitions and luminescence mechanisms in zero‐dimensional (0D) metal halides poses significant challenges, that are crucial for unlocking the full potential of tunable optical properties and diversifying their functional capabilities. Herein, we have designed two inter‐transformable 0D Cu(I)‐based metal halides, namely (C19H18P)2CuI3 and (C19H18P)2Cu4I6, through distinct synthesis conditions utilizing identical reactants. Their optical properties and luminescence mechanisms were systematically elucidated by experiments combined with density functional theory calculations. The bright cyan‐fluorescent (C19H18P)2CuI3 with high photoluminescence quantum yield (PLQY) of 77 % is attributed to the self‐trapped exciton emission. Differently, the broad yellow‐orange fluorescence of (C19H18P)2Cu4I6 displays a remarkable PLQY of 83 %. Its luminescence mechanism is mainly attributed to the combined effects of metal/halide‐to‐ligand charge transfer and cluster‐centered charge transfer, which effects stem from the strong Cu−Cu bonding interactions in the (Cu4I6)2− clusters. Moreover, (C19H18P)2CuI3 and (C19H18P)2Cu4I6 exhibit reversible structural phase transitions. The elucidation of the phase transitions mechanism has paved the way for an unforgeable anti‐counterfeiting system. This system dynamically shifts between cyan and yellow‐orange fluorescence, triggered by the phase transitions, bolstering security and authenticity. This work enriches the luminescence theory of 0D metal halides, offering novel strategies for optical property modulation and fostering optical applications. [ABSTRACT FROM AUTHOR]

Interferometric scattering (iSCAT) microscopy enables high‐speed and label‐free detection of individual molecules and small nanoparticles. Here we apply point spread function engineering to provide adaptive control of iSCAT images using spatial light modulation. With this approach, we demonstrate improved dynamic spatial filtering, real‐time background subtraction, focus control, and signal modulation based on sample orientation. LAY DESCRIPTION: In this paper, we apply spatial light modulation to manipulate the illumination properties of an interferometric scattering microscopy. This technique, called iSCAT, can image individual molecules and nanoparticles without the need for fluorescent labels. We added a digital display device that can modulate the pattern and phase of the laser illumination. This allows us to control the light used to make images. By changing how we use the light, we can optimise the contrast of our images, make rapid changes in focus without mechanical movement, and explore the alignment of gold nano rods. [ABSTRACT FROM AUTHOR]

This paper reviews and compares electrostatically actuated MEMS (micro-electro-mechanical system) arrays for light modulation and light steering in which transmission through the substrate is required. A comprehensive comparison of the technical achievements of micromirror arrays and microshutter arrays is provided. The main focus of this paper is MEMS micromirror arrays for smart glass in building windows and façades. This technology utilizes millions of miniaturized and actuatable micromirrors on transparent substrates, enabling use with transmissive substrates such as smart windows for personalized daylight steering, energy saving, and heat management in buildings. For the first time, subfield-addressable MEMS micromirror arrays with an area of nearly 1 m2 are presented. The recent advancements in MEMS smart glass technology for daylight steering are discussed, focusing on aspects like the switching speed, scalability, transmission, lifetime study, and reliability of micromirror arrays. Finally, simulations demonstrating the potential yearly energy savings for investments in MEMS smart glazing are presented, including a comparison to traditional automated external blind systems in a model office room with definite user interactions throughout the year. Additionally, this platform technology with planarized MEMS elements can be used for laser safety goggles to shield pilots, tram, and bus drivers as well as security personal from laser threats, and is also presented in this paper. [ABSTRACT FROM AUTHOR]

Technological advancements have enabled the active control of electromagnetic waves. Metalenses, known for their precision in wavefront shaping and functional versatility, represent a breakthrough in optical modulation. This study addresses the challenge of achieving dual-wavelength multifunctionality in metalens design. We developed and experimentally validated metalenses with polarization dual-function multiplexing at discrete mid-wave infrared wavelengths, demonstrating high phase fidelity and functional versatility. In addition, the proposed design method was extended to long-wave infrared wavelengths, showcasing its adaptability to different application scenarios. The application of spatial multiplexing significantly enhanced the performance of the metalenses, providing a promising solution for efficient and compact optoelectronic devices. [ABSTRACT FROM AUTHOR]

The compact and broadband optical switch with a large port count is demanded with the increasing communication capacity. In this article, a universal method for modeling the 1 × N switch using multimode interferometer (MMI) through transmission matrixes is proposed. Herein, the reasons for the narrowing of the operating bandwidth switch are analyzed. As a proof of concept, a wide bandwidth 1 × 4 switch, which has an insertion loss lower than 23.7 dB, and a cross talk better than −10 dB at 1550 nm are simulated, designed, and fabricated. The cross talk throughout the C band is lower than −8.5 dB. According to the experimental result, the 1 × 4 switch with four‐equal‐length modulating arms shows a 32 nm bandwidth for −10 dB cross talk which is 13 times larger than traditional switch. The switch realizes a multi‐port logic optical switch by modulation. The 1 × N switch based on the generalized Mach–Zehnder interferometer (GMZI) structure reduce the footprint significantly compared with the 1 × N switch consisting of a 1 × 2 switch cascade. It is believed that 1 × N switch based on GMZI structures is a promising solution to increase integration density. [ABSTRACT FROM AUTHOR]

Microgreens represent a valuable source of health-promoting compounds and also a research avenue, since such organisms have a very high plasticity related to environmental cues, allowing biotechnological development with low costs. Ocimum basilicum L. species naturally synthesize valuable, phenolic compounds, among which rosmarinic acid is most prominent. Within the current research, basil plantlets were grown for 10 days under either full spectrum light (white light) or modulated blue/red/far-red/UV spectrum elicitation with an additional factorization, by applying fertilization. Biomass accumulation reached up to 0.8 g/20 plantlets, while chlorophyll fluorescence was in the 0.75–0.78 range and remained uniform across treatments, indicating that no significant stress was exerted under modified light treatment. However, total phenolic contents and, in particular, rosmarinic acid contents, were markedly enhanced (up to 7.5 mg/g in the red cultivar) under modulated light treatment and fertilization, compared to full spectrum light. Moreover, in the red cultivar, gene expression was enhanced, 1.3–6.3 fold for genes coding for enzymes involved in phenylpropanoid synthesis pathways, such as phenylalanine ammonia lyase (PAL), tyrosine aminotransferase (TAT), Catechol-O-methyltransferase (COMT) and rosmarinic acid synthetase (RAS). Overall, light modulation coupled with fertilization led to the production of basil microgreens with up to 10% more total phenolics and up to 25% more rosmarinic acid. The results show that, using relatively simple growth equipment and setup, synthesis of health related, valuable compounds can be modulated in microgreens and, hence, serves as an avenue for businesses to develop cost effective biotechnological processes. [ABSTRACT FROM AUTHOR]

Owing to their intrinsic multiple physical dimensions and high parallelism, photons are superior to electrons when they act as information carriers. The independent and dynamic spatial modulations of multiple optical parameters of light are highly pursued in vital fields such as supercomputing, constellation satellite and optical communications, virtual/augmented reality, and holographic displays. To date, it is still challenging to accomplish this urgent task with a single element. Here, multiple optical parameter modulations are carried out via manipulation of the separate levels of a hierarchical structure. Photopatterning, light irradiation, and an electric field are adopted to regulate the patterned crystallizations, lattice constants, and tilt angles of blue‐phase liquid crystals (BPLCs). As the optical parameters are associated with the individual structural features, it enables binary reflectance and spatial geometric phase modulations, reversable wavelength shifting, and continuous reflectance variations with excellent independency. This work unlocks the multi‐degree modulation of light and addresses the miniaturization, integration, and dynamic and multifunctional tendencies of rapidly growing optical informatics. Owing to its merits of omnidirectional, independent control, and dynamic response, it may dramatically upgrade the performance of existing optics. [ABSTRACT FROM AUTHOR]

High finesse optical cavities have been the backbone of realizing narrow linewidth lasers to drive coherent excitations on dipole-forbidden transitions in atoms and ions for applications in atomic frequency standards. Over the past decade, increasing efforts have been made to develop technologies that enable the operation of all-optical atomic clocks in a portable form factor outside laboratory environments relying on transportable high-finesse optical cavities for field applications in positioning, navigation, timing (PNT) and communication. However, the compactness of such systems makes them more susceptible to environmental noises that limit their performance and stability. This review aims to address the underlying physics behind high-finesse optical cavities, cavity-based laser frequency stabilization schemes and various sources of noise arising from thermal, vibrational, acoustic, power and polarization fluctuations that impede the stability of portable optical cavities, as well as outline the strategies for minimizing their influences. We also discuss about the minimization of the residual amplitude modulation (RAM) noise that degrades the laser linewidth. In addition, our study encompasses a comparative analysis of various transportable, high-finesse optical cavity systems that are currently accessible for terrestrial and space-based metrology applications, as well as an exploration of the potential applications that these cavities can facilitate. We also review recent advancements in designing such systems and highlight their efforts for constructing ultra-stable, compact, high-finesse cavities for terrestrial and space-borne transportable all-optical atomic clocks. [ABSTRACT FROM AUTHOR]

Metasurfaces have become one of the most prominent research topics in the field of optics owing to their unprecedented properties and novel applications on an ultrathin platform. By combining graphene with metasurfaces, electrical tunable functions can be achieved with fast tuning speed, large modulation depth, and broad tuning range. However, the tuning efficiency of hybrid graphene metasurfaces within the short‐wavelength infrared (SWIR) spectrum is typically low because of the small resonance wavelength shift in this wavelength range. In this work, through the integration of graphene and silicon metasurfaces that support quasi‐bound states in the continuum (quasi‐BIC), the critical coupling as well as transmittance spectrum tuning is experimentally demonstrated. The spectrum tuning is substantial even with less than 30 nm resonance wavelength shift thanks to the high quality factor of quasi‐BIC metasurfaces. The tunable transmittance spectrum is measured using Fourier transform infrared spectroscopy (FTIR) with a modified reflective lens to improve the accuracy, and the electrical tuning is realized utilizing the “cut‐and‐stick” method of ion gel. At the wavelength of 3.0 µm, the measured transmittance change (ΔT  = Tmax  − Tmin) and modulation depth (ΔT/Tmax) can reach 22.2% and 28.9%, respectively, under a small bias voltage ranging from −2 to +2 V. This work demonstrates an effective way of tuning metasurfaces within the SWIR spectrum, which has potential applications in optical modulation, reconfigurable photonic devices, and optical communications. [ABSTRACT FROM AUTHOR]

Harnessing confined light on a subwavelength scale within Fano metasurfaces enhances light‐matter interaction on a flexible, low‐loss substrate. This approach enables the integration of ultra‐thin semiconducting films for designing low‐power, ultrafast switchable terahertz, and optical meta devices. Here, an ultra‐thin, ∼λ/6000 germanium overlayers of 25nm or 50nm is thermally evaporated onto a flexible Fano metallic metasurface to achieve ultrafast optical modulation of terahertz radiation. A remarkable 85% modulation depth with an ultrafast speed of 400 GHz is obtained in the resonant transmission. These ultrathin, flexible, and ultrafast functional metasurfaces pave the way for developing flexible terahertz active meta devices based on nanometric scale germanium films, offering the additional advantage of compatibility with complementary metal‐oxide‐semiconductor (CMOS) technology in microelectronics. [ABSTRACT FROM AUTHOR]

Doping and alloying induce defect states in atomically thin transition metal dichalcogenides (TMDCs), leading to strong carrier–phonon interactions. The robust excitonic behavior of these layered materials can be modified by injecting a high density of charge carriers. However, comprehending the influence of carrier–phonon and carrier–carrier interactions on the optical properties of 2D materials is crucial for their optoelectronic and photonic applications. Here, transient absorption (TA) spectroscopy is employed to demonstrate the modulation of the transient optical behavior of TMDCs through doping and excitation near Mott density. The TA spectra reveal broadening attributed to carrier–carrier and carrier–phonon interactions, with the broadening being particularly pronounced in vanadium (V) doped TMDCs due to the hybridization of defect and exciton transitions. Analysis of TA kinetics suggests the involvement of various carrier species in the carrier dynamics of TMDCs, with the influence of mid‐gap carriers dominating at higher excitation densities. Nonetheless, the presence of strong carrier–phonon coupling in V‐doped TMDCs is demonstrated by temperature‐dependent Raman and photoluminescence spectroscopy. The results reveal that the enhanced coupling between acoustic phonons and carriers can lead to multiphonon emission. The findings of this study hold promise for controlling the optical response of TMDCs in ultrafast optoelectronic applications. [ABSTRACT FROM AUTHOR]

Nowadays, multifunctional compounds emerge as an intriguing category of materials with potential applications in nanophotonics. Particularly, organic compounds stand out due to their bio‐friendly characteristics. In this study, a thiophene‐based carboxaldehyde is designed to address the challenges of the 21st century. The experimental approach substantiates its highly attractive molecular architecture, demonstrating simultaneous efficiency in light generation, modulation, and amplification. Employing the Maker fringes technique as a monitoring tool for nonlinear optical responses, through a comparative experimental method, efficient and repeatable higher harmonics of light generation, including double and triple frequencies are observed. Utilizing a typical pump‐probe laser setup, optically‐driven light modulation under a UV source at a frequency of 1 kHz is showcased. Furthermore, through optical pumping, a Boltzmann energy distribution inversion leading to radiative decay is achieved, specifically, effectively amplified emission reminiscent of random lasing in both liquid and solid states. Complementary quantum‐chemical calculations supported the experimental findings, contributing to a comprehensive understanding of the material's scientific properties. The outcomes of this study underscore the significant potential of organic materials in terms of versatility, indicating their promising applications in nano(bio)photonics and opto‐electronics. [ABSTRACT FROM AUTHOR]

Bifunctional devices combining display and energy storage capabilities are crucial for next-generation optoelectronic technology. This study investigates the application of nickel oxide (NiO) thin films for bifunctional electrochromic energy storage systems. The amorphous Ni(OH) 2 thin films were electrodeposited with a focus on their time-dependent properties. The Scharifker-Hills model revealed a mixed nucleation process during the electrodeposition. The deposited thin films were examined for their physicochemical properties using X-ray diffraction (XRD), micro-Raman spectroscopy, X-ray photoelectron Spectroscopy (XPS), and morphological studies. Rietveld refinement of the XRD pattern confirmed a cubic NiO polycrystalline phase, while XPS identified Ni3+ as the dominant oxidation state. Significant morphological changes were observed with the varying deposition time. The NiO electrode deposited for 120 minute exhibited optimal characteristics including the highest areal capacitance of 161.77 mF/cm2, along with excellent cyclic stability of 96.54 % even after 2000 cyclic voltammetry cycles. The electrochromic study demonstrated optical modulation ranging within 55–82 % at 532 nm, with a maximum coloration efficiency of 86.90 cm2/C. This research demonstrates the viability of NiO thin films as bifunctional electrochromic energy storage systems and the advancement of optoelectronic devices that integrate display and energy storage functionalities. [ABSTRACT FROM AUTHOR]

Optoelectronic memristors, which possess the potential capacities of in‐sensor computing, promote the development of highly efficient neuromorphic vision. In this work, a novel optoelectronic memristor based on chlorophyll (Chl) heterojunction is proposed, which consists of two types of Chl derivatives (zinc methyl 3‐devinyl‐3‐hydroxymethyl‐pyropheophorbide‐a and methyl 131‐deoxo‐131‐dicyanomethylene‐pyropheophorbide‐a). Chl heterojunction improves the optoelectronic performance of the device due to its ability to efficiently separate photogenerated electron‐hole pairs. The device exhibits the synaptic potentiation and inhibition behaviors under light stimulations of 430 and 730 nm, respectively, thus demonstrating the all‐optically modulated synaptic plasticity. The switching mechanism can be attributed to the photo‐ionization/deionization of oxygen vacancies at the zinc oxide (ZnO)/Chl interface. In addition, the image pre‐processing functions of contrast enhancement and noise reduction are implemented in a memristive array. In particular, the edge detection function has been implemented by utilizing reversible optical modulation, which highlights the object outline. The optoelectronic memristor based on the Chl heterojunction proposed here provides a promising foundation for advancing neuromorphic vision. [ABSTRACT FROM AUTHOR]

By combining molecular dynamics (MD) simulations and density functional theory (DFT), the influence of dye structure on the optical modulation properties of negative-mode guest–host liquid crystal (GHLC) systems was systematically investigated. Firstly, the reliability of the simulation method was validated by comparing the performance parameters of the GHLC system obtained from simulations with those from experimental results. Subsequently, a series of guest dye molecules, along with their mixtures with negative dielectric anisotropy mesogens, were designed and analyzed. This exploration focused on how variations in dye terminal chain lengths, substitution positions, and substituent group properties affect dye molecular geometry, dye alignment within the host, transition dipole orientation, absorption spectra, and electronic excitation properties. Our findings suggest that dye molecules with a flexible terminal chain substitution of five carbon atoms, positioned at the 2 and 6 locations on the anthraquinone core, exhibit higher order parameters, favorable for enhancing dichroic performance. Moreover, introducing different α-substituents further influences the dye orientation and electronic behavior within the host. These results highlight that structural modifications of anthraquinone-based dyes allow for the design of high-dichroic-ratio materials with customized absorption properties. Overall, our results provide a beneficial understanding of the structure–property relation in GHLC systems, offering valuable guidance for designing high-performance dye molecules and advanced optoelectronic materials in future research. [ABSTRACT FROM AUTHOR]

This research focuses on the integration of an opto-satellite system based on Free Space Optical Communication (OWC) within DVB-RCS2 chains, implementing 16-QAM modulation techniques and Optical Time Division Wavelength Multiplexing (OTDMWDM). A co-simulation framework combining the MATLAB and OptiSystem environments is adopted to evaluate the system's performance. Key performance indicators, such as Bit Error Rate (BER) and Q factor, are meticulously analyzed to quantify the effectiveness of the proposed approach. The results obtained demonstrate notable improvements in transmission reliability and signal quality, highlighting the potential of OWC to optimize DVB-RCS2 standards. This study significantly contributes to the development of innovative solutions in the field of satellite communications, paving the way for more efficient and resilient systems. [ABSTRACT FROM AUTHOR]

Negative photoconductive devices exhibit a significant reduction in conductivity under illumination, enabling high-contrast optical modulation and promising great potential in optics. In this study, an ITO/BFCO/TiO2/FTO device was simply fabricated through a synergistic application of sol-gel and magnetron sputtering techniques. Interestingly, the ferroelectric polarization can be reversibly modulated by a low bias voltage in the ITO/BFCO/TiO2/FTO device, thereby exhibiting bipolar voltage dependent reversible behavior of positive and negative photoconductivity. This mechanism has been discussed, where the combined effect of illumination and applied voltage induces internal polarization reversal in Bi2FeCrO6, leading to a transition in the resistance state from low to high. This transition results in an elevation of the energy band, thereby impeding the migration of charge carriers. Additionally, femtosecond laser transient absorption spectroscopy reveals redshift in the initial absorption peak, indicating changes in the band structure induced by illumination, crucial for understanding carrier dynamics in a non-equilibrium state. [ABSTRACT FROM AUTHOR]

Metalens can achieve arbitrary light modulation by controlling the amplitude, phase, and polarization of the incident waves and have been applied across various fields. This paper presents a color router designed based on metalens, capable of effectively separating spectra from visible light to near-infrared light. Traditional design methods for meta-lenses require extensive simulations, making them time-consuming. In this study, we propose a deep learning network capable of forward prediction across a broad wavelength range, combined with a particle swarm optimization algorithm to design metalens efficiently. The simulation results align closely with theoretical predictions. The designed color router can simultaneously meet the theoretical transmission phase of the target spectra, specifically for red, green, blue, and near-infrared light, and focus them into designated areas. Notably, the optical efficiency of this design reaches 40%, significantly surpassing the efficiency of traditional color filters. [ABSTRACT FROM AUTHOR]

Lasers with narrow linewidths and long-term frequency stability are required in various applications such as precision measurement and optical frequency reference. Here, we propose a hybrid method that combines techniques of optical feedback and optical heterodyne modulation locking to an external Fabry-Perot cavity to reduce the linewidth and frequency drift of the laser. The method is demonstrated on a distributed feedback laser with a free-running linewidth of 2 MHz. The frequency noise power density spectrum shows a reduction of 50 dB in the low-frequency range and 30 dB for white noise, and the linewidth has been reduced to 20 kHz. The lock can be maintained for days. This method can be applied to various lasers of different wavelengths. [ABSTRACT FROM AUTHOR]

We present a new partially coherent pulsed source with spatiotemporal coupling. The stochastic optical pulse, which we call a spatiotemporal coupled cosine–Gaussian-correlated Schell-model pulsed (STC–CGCSMP) source, has its spatial and temporal (or spectral) dimensions coupled by a stochastic factor. Within the frame of the extended Collins formula, we derive the expression for the two-point, two-frequency cross-spectral density (CSD) function as this such source propagates through an ABCD optical system. We then simulate the spectral density, the two-point, two-frequency CSD, and the spectral degree of coherence to discuss how the spatiotemporal coupling factor affects the beam structure during transmission. Our theoretical models enrich the classical theory of propagating stochastic optical pulses and may provide a feasible method for further exploration of novel kinds of optical field modulation. [ABSTRACT FROM AUTHOR]

This study proposes a novel plasmonic optical modulator integrating the phase‐change material germanium‐antimony‐tellurium (GST) with a silicon carbide (SiC) waveguide for telecom applications. The design utilizes a 10 nm GST cladding layer and a 290 nm thick, 100 nm wide SiC ridge waveguide, with gold electrodes enabling electrothermal switching of GST between amorphous and crystalline states. Comprehensive simulations spanning optical, electrical‐thermal, and opto‐thermal domains investigated the modulator's performance. Optical simulations examine the effects of wavelength, ridge width, and GST thickness on effective refractive index, confinement factor, and effective area. Electrical‐thermal simulations determines voltage pulse parameters for phase transitions and analyzed temperature distributions. Opto‐thermal simulations explored temperature's influence on the effective refractive index during phase transitions. Results demonstrate the modulator's potential, achieving 160 Mb s−1 at 1.55 µm. The SiC‐GST integration offers high thermal conductivity, low thermo‐optic coefficient, and significant refractive index contrast between GST phases, enabling efficient light modulation for high‐performance, compact, energy‐efficient optical modulators advancing integrated photonics. [ABSTRACT FROM AUTHOR]

Presented here is long-range distributed vibration sensing based on internal-modulation optical frequency domain reflectometry (OFDR). In the proposed system with internal modulation, a silicon-based photonic-chip laser is used as the laser source, and by controlling the output voltage curve of an arbitrary waveform generator to induce temperature change in the external cavity of the laser, a 10-GHz optical frequency tuning range is achieved. The complexity of the proposed internal-modulation system is lower than that of the traditional external-modulation OFDR system that combines a narrow-linewidth laser with a single-sideband modulator to achieve wavelength tuning. Cross-correlation analysis is used as a sensing mechanism to evaluate the similarity between Rayleigh scatter signals and to achieve vibration event localization. Experimental comparison is made of the vibration sensing performance of the external- and internal-modulation systems, and for a vibration event generated at a distance of 100.95 km, they locate it with a sensing spatial resolution of 43.0 m and 16.8 m, respectively. The results indicates that the proposed distributed vibration sensing based on internal modulation has better sensing performance and lower complexity compared to the traditional external-modulation system. In addition, the proposed system is single-ended and involves no optical amplification, which makes it very suitable for ultra-long-range sensing. ARTICLE HIGHLIGHTS: • The sensing range of the proposed distributed vibration sensing based on OFDR is up to 100 km with no optical amplification. • The system complexity for long-distance vibration sensing is reduced significantly. • Vibration event location is achieved with a finer sensing spatial resolution of 16.8 m. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effect of annealing temperature on the structural, morphological, and electrochemical properties of tungsten trioxide (WO3) films, fabricated via electrodeposition and annealed at 50 °C, 250 °C, and 450 °C. Structural analysis using X-ray diffraction (XRD) revealed temperature-induced modifications, transitioning from amorphous to crystalline phases. Morphological studies by field emission scanning electron microscopy (FESEM) demonstrated an increase in grain size with temperature (31 nm, 48 nm, and 53 nm) and the formation of cracks at higher annealing temperatures. Electrochemical characterization showed that the WO3 film annealed at 250 °C exhibited superior redox activity, enhanced ion diffusion, and excellent reversibility. Optical studies highlighted its exceptional performance, with 79.35% optical modulation, a coloration efficiency of 97.91 cm2/C, and rapid switching times (9.8 s for coloration and 7.5 s for bleaching). Furthermore, long-term cycling tests confirmed minimal degradation after 5000 cycles, demonstrating durability. This work provides a comprehensive understanding of the annealing temperature's impact on WO3 films and underscores the novelty of achieving optimal electrochromic (EC) performance through temperature tuning, advancing the design of energy-efficient smart materials. [ABSTRACT FROM AUTHOR]

This study introduces the development of a W-M1.0 electrochromic film, characterized by a "coral"-like TiO2@WO3 heterostructure, synthesized via a hydrothermal process leveraging the inherent instability of MXene. The film showcases exceptional electrochromic performance, with a coloring response time of 2.8 s, a bleaching response time of 4.6 s, and a high coloring efficiency of 137.02 cm2C−1. It also demonstrates a superior light modulation ability of 73.83% at 1033 nm. Notably, the W-M1.0 film exhibits remarkable cyclic stability, retaining over 90% of its initial light modulation capacity after 4000 cycles, outperforming many existing electrochromic materials. The film's enhanced performance is credited to its coral-like structure, which boosts the specific surface area and promotes ion transport, and the TiO2@WO3 heterojunctions, which enhance charge transfer and stabilize the material. Devices fabricated with the W-M1.0 film as the cathode and a PB film as the anode exhibit a seamless transition from dark blue to colorless, underscoring their potential for smart window and dynamic glass applications. [ABSTRACT FROM AUTHOR]

Tungsten oxide (WO3) electrochromic devices are obtaining increasing interest due to their color change and thermal regulation. However, most previous work focuses on the absorption or transmission spectra of materials, rather than the optical parameters evolution in full spectrum in the electrochromic processes. Herein, we developed a systematic protocol of ex situ methods to clarify the evolutions of subtle structure changes, Raman vibration modes, and optical parameters of WO3 thin films in electrochromic processes as stimulated by dosage-dependent Li+ insertion. We obtained the below information by ex situ spectroscopic ellipsometry. (1) Layer-by-layer Li+ embedding mechanism demonstrated by individual film thickness analysis. (2) The details of its optical leap in the Brillouin zone in the full spectral. (3) The optical constants varied with the Li+ insertion in the ultraviolet, visible, and near-infrared bands, demonstrating the potential for applications in chip fabrication, deep-sea exploration, and optical measurements. (4) Simulated angular modulation laws of WO3 films for full spectra in different Li+ insertion states. This ex situ method to study the optical properties of electrochromic devices are important for monitoring phase transition kinetics, the analysis of optical leaps, and the study of ion diffusion mechanisms and the stoichiometry-dependent changes in optical constants over the full spectral. This work shows that electrochromic films in Li+ surface permeation can be applied in the field of zoom lenses, optical phase modulators, and other precision optical components. Our work provides a new solution for the development of zoom lenses and a new application scenario for the application of electrochromic devices. [ABSTRACT FROM AUTHOR]

In order to break the diffraction limit and improve the imaging resolution of optical microscope, in this article, we theoretically deduced the influence of phase difference on imaging resolution under coherent illumination. As the phase difference increased, the resolution improved gradually. Inspired by this conclusion, a super-resolution optical imaging system based on phase modulation was proposed and simulated. An optical mask was designed to generate additional phase difference for the adjacent area at the sample's surface, and the influence of its structural parameters was analyzed numerically. The simulation results preliminarily confirm the feasibility of this scheme, laying the foundation for a more optimal and comprehensive super-resolution imaging scheme. Due to its advantages of high resolution, a wide field of view, and being compatible, this non-fluorescence super-resolution imaging scheme is worthy of further research and application. [ABSTRACT FROM AUTHOR]

The refractive index of the lenses used in optical designs varies with wavelength, causing light rays to fail when focusing on a single plane. This phenomenon is known as chromatic aberration (CA), chromatic distortion, or color fringing, among other terms. Images affected by CA display colored halos and experience a loss of resolution. Fully achromatic systems can be achieved through complex and costly lens designs and/or computationally when digital sensors capture the image. In this work, we propose using the wavefront coding (WFC) technique with a trefoil-shaped phase modulation plate in the optical system to effectively increase the resolution of images affected by longitudinal chromatic aberration (LCA), significantly simplifying the optical design and reducing costs. Experimental results with three LEDs simulating RGB images verify that WFC with trefoil phase plates effectively corrects longitudinal chromatic aberration. Transverse chromatic aberration (TCA) is corrected computationally. Furthermore, we demonstrate that the optical system maintains depth of focus (DoF) for color images. [ABSTRACT FROM AUTHOR]

In this work, we theoretically simulate the modulation of a soliton molecule that has an initial chirped Gaussian pulse shape in a 1 μm extra-cavity optical fiber modulation system. Different soliton parameters in orthogonal polarizations are applied to achieve controllable optical solitons' output with specific properties in the time/frequency domain. For instance, when the phase difference is changed, both pulse shapes' and corresponding optical spectra's peak intensities will have a sudden change when the orthogonal phase difference is π/2. These simulation results provide a beneficial reference value for extra-cavity shaping of different solitons that come from nonlinear optical systems. Optimally, the reported results could pave the groundwork for industrial growth in ultrafast laser design. [ABSTRACT FROM AUTHOR]

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In an optically excited semiconductor micromechanical structure, photogenerated carriers (plasma waves) can produce elastic deformations (local strains and stresses)–plasmaelastic (PE) deformations. On the other hand, the generation of excess carriers will produce heat due to carrier thermalization and recombination processes. The generated heat can produce other elastic deformations–thermoelastic (TE) deformations. For these two components of elastic deformation, it is possible to consider two types of elastic displacements (two mods of elastic vibrations): elastic expanding and elastic bending. A theoretical model of the photoacoustic (PA) signal for optically excited Si membranes is given, which includes thermal diffusion (TD), TE, and PE mechanisms, in order to study elastic expansion and bending. The relations for the PA amplitude and the phase of elastic expanding and bending in the excited membrane are derived. Analysis of the PA signal indicates that the TD component is dominant for all thicknesses and practically the entire range of observed frequencies. The calculated PA amplitude and phase spectra show that the PA elastic expanding component has a significant influence on the total PA signal at low frequencies. On the other side, the calculated PA spectra show that the PA elastic bending component has a significant influence on the total PA signal at high frequencies. Experimental PA signals of Si membranes were measured using the sample-gas-microphone detection technique with a transmission configuration in relation to the modulation frequency of the optical excitation for different membrane thicknesses. The experimental PA spectra were compared with the theoretical ones. [ABSTRACT FROM AUTHOR]