Hasil untuk "Applied optics. Photonics"

Xiangang Luo

Over the past few decades, digital optical technologies have undergone significant advancements and revolutionized the optical science and technologies. It not only challenges the classical optical frameworks (e.g., the laws of refraction and reflection, and the optical diffraction limit) but also enables unprecedented control over light–matter interactions. Early research in the digital optics field predominantly focused on validating fundamental principles and demonstrating proof-of-concept applications. Recently, the fast breakthroughs in computational electromagnetics, artificial intelligence, and cross-scale nanofabrication have dramatically improved the performances of digital optical components. These advancements are now propelling the field toward addressing a pivotal challenge: How can digital optics be harnessed to manipulate optical information and energy under complex and harsh environments? This rapidly evolving frontier has garnered substantial attention within the photonics community, establishing it as a pivotal enabler for next-generation optical/photonic technologies. This Perspective briefly reviews the history and current landscape of digital optics, with a focus on discussing its future development and challenge toward optical intelligent agents (OIAs).

Oliver Vauderwange, Sofia Hämmerle, Stefano Gampe et al.

The conceptual restructuring and redesign of the curriculum in media technology has succeeded in creating a broad platform for practical projects and applied research. By using gamification as an innovative method to enhance motivation, learning success, and learner participation, further development is intended to be achieved.

S. S. Kundu, A. Srivastava, A. Kundu et al.

The eastern parts of India, Bangladesh, and the North Eastern Region (NER) of India are among the world's most active areas for thunderstorms and lightning, resulting in substantial human and livestock casualties annually. Lightning strikes cause over 500 fatalities in India and approximately 300 in Bangladesh each year, alongside significant property damage and loss of wildlife, such as the death of 18 elephants in Assam in 2021. To mitigate the devastating effects, this study developed a pilot-scale forecasting system for lightning and thunderstorms over the NER of India, leveraging space-based platforms, ground-based detectors, and numerical models. Data sources included the WWLLN (World Wide Lightning Location Network), India's national lightning detection network, Doppler Weather Radar (DWR), and satellite data from INSAT 3D/3DS. The WRF-ELEC model was employed for forecasting, assimilating lightning data via nudging techniques, and achieving forecasts with up to 75% accuracy for lead times of up to four hours. A GIS-based system was used to track convective systems and predict impacted areas at a village level with a one-hour lead time. This system integrates lightning detection, satellite imagery, and DWR data, enabling the identification of affected populations and land use, thereby aiding in disaster preparedness and mitigation. The study demonstrates the potential of integrating earth observation data, in-situ measurements, and numerical models to provide location-specific and time-sensitive lightning forecasts. Coupled with awareness campaigns on safety measures during lightning, this approach offers a robust mechanism to reduce casualties and property damage. Scaling this system beyond the pilot region could significantly enhance disaster risk reduction in other lightning-prone regions.

Umar Farooq, Amalia Miliou

This article presents the decision feedback equalizer (DFE), the maximum likelihood detection (MLD), and the radius-directed equalization (RDE) algorithms designed in MATLAB-R2018a to equalize the received signal in a dispersive optical link up to 120 km. DFE is essential for improving signal quality in several communication systems, including WiFi networks, cable modems, and long-term evolution (LTE) systems. Its capacity to mitigate inter-symbol interference (ISI) and rapidly adjust to channel variations renders it a flexible option for high-speed data transfer and wireless communications. Conversely, MLD is utilized in applications that require great precision and dependability, including multi-input–multi-output (MIMO) systems, satellite communications, and radar technology. The ability of MLD to optimize the probability of accurate symbol detection in complex, high-dimensional environments renders it crucial for systems where signal integrity and precision are critical. Lastly, RDE is implemented as an alternative algorithm to the CMA-based equalizer, utilizing the idea of adjusting the amplitude of the received distorted symbol so that its modulus is closer to the ideal value for that symbol. The algorithms are tested using a converged 5G mm-wave analog radio-over-fiber (A-RoF) system at 60 GHz. Their performance is measured regarding error vector magnitude (EVM) values before and after equalization for different optical fiber lengths and modulation formats (QPSK, 16-QAM, 64-QAM, and 128-QAM) and shows a clear performance improvement of the output signal. Moreover, the performance of the proposed algorithms is compared to three commonly used algorithms: the simple least mean square (LMS) algorithm, the constant modulus algorithm (CMA), and the adaptive median filtering (AMF), demonstrating superior results in both QPSK and 16-QAM and extending the transmission distance up to 120 km. DFE has a significant advantage over LMS and AMF in reducing the inter-symbol interference (ISI) in a dispersive channel by using previous decision feedback, resulting in quicker convergence and more precise equalization. MLD, on the other hand, is highly effective in improving detection accuracy by taking into account the probability of various symbol sequences achieving lower error rates and enhancing performance in advanced modulation schemes. RDE performs best for QPSK and 16-QAM constellations among all the other algorithms. Furthermore, DFE and MLD are particularly suitable for higher-order modulation formats like 64-QAM and 128-QAM, where accurate equalization and error detection are of utmost importance. The enhanced functionalities of DFE, RDE, and MLD in managing greater modulation orders and expanding transmission range highlight their efficacy in improving the performance and dependability of our system.

Zhao-Song Li, Chao Liu, Xiao-Wei Li et al.

Abstract As a frontier technology, holography has important research values in fields such as bio-micrographic imaging, light field modulation and data storage. However, the real-time acquisition of 3D scenes and high-fidelity reconstruction technology has not yet made a breakthrough, which has seriously hindered the development of holography. Here, a novel holographic camera is proposed to solve the above inherent problems completely. The proposed holographic camera consists of the acquisition end and the calculation end. At the acquisition end of the holographic camera, specially configured liquid materials and liquid lens structure based on voice-coil motor-driving are used to produce the liquid camera, so that the liquid camera can quickly capture the focus stack of the real 3D scene within 15 ms. At the calculation end, a new structured focus stack network (FS-Net) is designed for hologram calculation. After training the FS-Net with the focus stack renderer and learnable Zernike phase, it enables hologram calculation within 13 ms. As the first device to achieve real-time incoherent acquisition and high-fidelity holographic reconstruction of a real 3D scene, our proposed holographic camera breaks technical bottlenecks of difficulty in acquiring the real 3D scene, low quality of the holographic reconstructed image, and incorrect defocus blur. The experimental results demonstrate the effectiveness of our holographic camera in the acquisition of focal plane information and hologram calculation of the real 3D scene. The proposed holographic camera opens up a new way for the application of holography in fields such as 3D display, light field modulation, and 3D measurement.

S. Kim, Y. Lee, Y. Lee et al.

This study presents a Historic Building Information Modeling (HBIM)-based approach for the digital restoration and documentation of lost wooden architectural heritage. The approach was applied to Building 1-2 of Hyeumwonji, the site of a temporary Goryeo Dynasty palace in Paju, South Korea. To reconstruct this lost structure, we combined historical and archaeological analyses to estimate the original design and generated blueprints that guided the HBIM-based 3D model of the building. We collected LiDAR point cloud data from the site, aligned them with the HBIM model, and visualized the integrated result using Unreal Engine 5. The outcome was a comprehensive virtual restoration comprising 13,814 individual building elements. This case study demonstrates that, even with minimal physical remains, wooden heritage sites can be digitally restored by leveraging HBIM and historical reasoning. It also highlights the strengths of HBIM in version tracking, incorporation of historical updates, and systematic documentation throughout the restoration process. Compared to traditional 2D CAD-based restoration methods, the HBIM approach offers significant advantages in terms of updatability, data integration, and long-term preservation of restoration data. Overall, the project illustrates how combining rigorous historical analysis with advanced digital modeling can revive lost heritage architecture in virtual form, providing a rich resource for research and conservation.

Tao Wang, Qi Luo, Fengyuan Cui et al.

Given the recent success of metasurfaces in free-space applications, these concepts can be leveraged to an even larger extent in on-chip waveguide systems. The in-plane diffractive metasurfaces enable the manipulation of guiding waves in the multimode regime with greater parallelism than conventional single-mode or few-mode waveguides, leading to exciting opportunities in signal processing and optical computing systems. Beam focusing is one of the basic functionalities of wavefront shaping, which can be implemented using phase gradient metalenses consisting of arrays of meta-atoms. The meta-atoms are mainly realized by etched trenches with varying lengths, which are assembled into a one-dimensional transmit array with a specific phase response. However, this kind of periodic arrayed structure has significantly limited design freedom compared to its free-space counterparts. Here, we propose a digital metalens that consists of a seamless array of pixelated unit cells, which are engineered via inverse design. In contrast to conventional focusing metalenses based on transmit arrays, highly functional digital metalenses have been demonstrated: (1) achromatic focusing lens; (2) extended depth of focus (EDOF) lens; (3) Airy beam lens. These devices were fabricated on a silicon photonic platform and characterized in near-infrared. The intersection of digital structures and algorithm-driven optimizations offers greater versatility for on-chip wavefront shaping.

Svetlana S. Konnova, Pavel A. Lepilin, Anastasia A. Zanishevskaya et al.

Biosensor technologies in medicine, as in many other areas, are replacing labor-intensive methods of monitoring human health. This paper presents the results of experimental studies on label-free sensors based on a hollow core microstructured optical waveguide (HC-MOW) for human blood serum analysis. The MOWs with a hollow core of 247.5 µm in diameter were manufactured and used in our work. These parameters allow the hollow core to be filled with high-viscosity solutions due to the capillary properties of the fiber. Calculations of the spectral properties of the HC-MOW fiber were carried out and experimentally confirmed. Twenty-one blood serum samples from volunteers were analyzed using standard photometry (commercial kits) and an experimental biosensor. The obtained transmission spectra were processed by the principal component analysis method and conclusions were drawn about the possibility of using this biosensor in point-of-care medicine. A significant difference was shown between the blood serum of healthy patients and patients with confirmed diagnoses and a long history of cardiovascular system abnormalities. Algorithms for spectra processing using the Origin program are presented.

Manuel F. M. Costa, Sandra Franco

The remarkable development of pure and applied research in the fields of optics and photonics in the past few decades has reinforced the need to position optics among the major fields of science that are considered to have remarkable, multi-fold impacts on everyday life and on our modern society [...]

Flavio Augusto de Melo Marques, Otávio José de Rezende Silveira, Ivys Francisco de Moura Domingues et al.

This article describes the application of instrumentation in the teaching of optics and photonics within the Physical Engineering program at the Federal University of Lavras in Brazil. The reported experience involved the revitalization and automation of an old and damaged spectrophotometer, which was transformed into a pedagogical tool. By using electronic components such as Arduino, infrared sensors, stepper motors, and photodetectors, the spectrophotometer was reconfigured to operate with reliability. The process included the development of a user-friendly graphical interface, enabling real-time visualization of spectra and offering multiple functionalities such as diffraction grating adjustment and light intensity control. The project provided a valuable resource for practical classes in optics and photonics and encouraged active student participation in all stages of development and implementation. This approach highlighted the importance of integrating theory and practice in engineering and physics education, resulting in deeper and more meaningful learning.

M. H. Dwech, M. A. Habeeb, A. H. Mohammed

We study the impact of (MnO2–ZrO2) nanoparticles on optical properties of (PVA) polymer. Several samples were produced with different weight ratios of (MnO2–ZrO2) nanoparticles. To prepare the selected samples, the casting method is used. To record the absorption spectrum, wavelengths of 200–1100 nm are applied. We have determined the absorption coefficient, energy gap for indirect transitions (forbidden and allowed), optical constants (such as the dielectric constant with its imaginary and real parts, refractive index, and attenuation coefficient), and optical conductivity. The results indicate that there is a proportional relationship between the optical constants and the concentration of (MnO2–ZrO2) nanoparticles, which means that an increase of the concentration of (MnO2–ZrO2) nanoparticles leads to an increase of the optical constants, while the transmission decreases. Additionally, the optical energy gap decreases from 4.83 eV to 3.4 eV and from 4.65 eV to 3.28 eV with increasing the concentration of (MnO2–ZrO2) nanoparticles for allowed and forbidden indirect transitions, respectively. These results can be considered as key ones for the use of (PVA-MnO2–ZrO2) nanocomposites in various fields such as optoelectronics and photonics.

I. Cárdenas-León, R. Morales-Ortega, M. Koeva et al.

According to the KNMI Klimaatsignaal’21, the average surface temperature in The Netherlands has increased by 2.3°C between 1901 and 2020. Moreover, The Netherlands is also experiencing more frequent and intense heatwaves. Urban development significantly impacts the environmental conditions of a city, influencing thermal comfort and human well-being. To deal with these problems, municipalities across the country have been tasked to find ways to measure, understand, and find solutions to the increasing temperatures, specifically in urban areas. Because of this, several contrasting urban heat maps have been produced using different metrics and methods by different agencies. Koopman et al. presented a methodology for a standardized urban heat map at a 1-m spatial resolution to unify the stress tests by selecting the Physical Equivalent Temperature (PET) as a metric for heat stress. The PET is a key indicator in bio-meteorology, quantifying the combined effects of various environmental factors on human thermal perception. Despite its utility, widespread adoption of PET-based assessments by municipalities remains limited. To address this gap, this paper presents the development of a Digital Twin framework using PET analysis, enabling a collaborative, nondestructive, and cost-effective assessment of urban interventions’ impact on thermal conditions. Leveraging geoprocessing workflows and geospatial data, our framework allows for real-time PET calculations and scenario testing, facilitating informed decision-making by urban planners. The framework was tested and applied for Enschede, Netherlands, demonstrating its efficacy in visualizing current conditions, projecting future scenarios, and evaluating intervention strategies. Feedback from urban planners highlighted the tool’s usability and potential for enhancing community engagement in urban planning processes.

Guijun Li, Man-Chun Tseng, Yu Chen et al.

Abstract The growing focus on enhancing color quality in liquid crystal displays (LCDs) and organic light-emitting diodes (OLEDs) has spurred significant advancements in color-conversion materials. Furthermore, color conversion is also important for the development and commercialization of Micro-LEDs. This article provides a comprehensive review of different types of color conversion methods as well as different types of color conversion materials. We summarize the current status of patterning process, and discuss key strategies to enhance display performance. Finally, we speculate on the future prospects and roles that color conversion will play in ultra-high-definition micro- and projection displays.

P. Lalanne, M Chen, C. Rockstuhl et al.

Optical metasurfaces are conventionally viewed as organized flat arrays of photonic or plasmonic nanoresonators, also called metaatoms. These metasurfaces are typically highly ordered and fabricated with precision using expensive tools. However, the inherent imperfections in large-scale nanophotonic devices, along with recent advances in bottom-up nanofabrication techniques and design strategies, have highlighted the potential benefits of incorporating disorder to achieve specific optical functionalities. This review offers an overview of the key theoretical, numerical, and experimental aspects related to the exploration of disordered optical metasurfaces. It introduces fundamental concepts of light scattering by disordered metasurfaces and outlines theoretical and numerical methodologies for analyzing their optical behavior. Various fabrication techniques are discussed, highlighting the types of disorder they deliver and their achievable precision level. The review also explores critical applications of disordered optical metasurfaces, such as light manipulation in thin film materials and the design of structural colors and visual appearances. Finally, the article offers perspectives on the burgeoning future research in this field. Disordered optical metasurfaces offer a promising alternative to their ordered counterparts, often delivering unique functionalities or enhanced performance. They present a particularly exciting opportunity in applications demanding large-scale implementation, such as sustainable renewable energy systems, as well as aesthetically vibrant coatings for luxury goods and architectural designs.

D. Julien-Neitzert, E. Leung, N. Islam et al.

Integrated circuit technology enables the scaling of circuit complexity and functionality while maintaining manufacturability and reliability. Integration is expected to play an important role in quantum information technologies, including in the highly demanding task of producing the classical signals to control and measure quantum circuits at scales needed for fault-tolerant quantum computation. Here we experimentally characterize the cryogenic performance of a miniaturized photonic integrated circuit fabricated by a commercial foundry that down-converts classical optical signals to microwave signals. The circuit consists of waveguide-integrated germanium PIN photodiodes packaged using a scalable photonic wire bonding approach to a multi-channel optical fiber array that provides the optical excitation. We find the peak optical-to-microwave conversion response to be $\sim 150 \pm 13$ mA/W in the O-band at 4.2 K, well below the temperature the circuit was designed for and tested at in the past, for two different diode designs. The second diode design operates to over 6 GHz of 3 dB bandwidth making it suitable for controlling quantum circuits, with improvements in bandwidth and response expected from improved packaging. The demonstrated miniaturization and integration offers new perspectives for wavelength-division multiplexed control of microwave quantum circuits and scalable processors using light delivered by optical fiber arrays.

C. Betters, Liwei Li, C. Martijn de Sterke

This focus issue provides an overview of current applied optics research activities in the Sydney region in Australia, illustrating the breadth and depth of the research carried out in the region. Below we first give an overview of some of the history of optics research in Sydney and then brief descriptions of the 10 papers in the issue.

A. C. Amaro de Faria Júnior, V. Mazur, G. Woitovetch

The interaction of light with matter can generate different types of scattering that can be applied to quantum optics, photonics and integrated optics appropriately. The generation of certain pulses in certain waveguides can produce certain nonlinear optical pulses with important properties such as low energy and information loss applied, for example, to communication systems and quantum information. The method we describe is based on the generation and propagation of nonlinear optical pulses in multidimensional material structures: waveguides in 1 dimension, planar systems in 2 dimensions and crystalline systems in 3 dimensions. These structures can be appropriately designed to generate nonlinear and quantum optical pulses depending on the crystal structure and electrical susceptibility of the material. These optical pulses can be appropriately characterized whose respective scattering signals can be identified and processed providing an application basis for emerging technologies for transmission and processing systems based on quantum optics and quantum computing.

Alba de las Heras, A. I. Gómez-Varela, M. Tomás et al.

The COVID pandemic is forcing the renewal of scientific conferences, offering opportunities to introduce technological and inclusive developments. Our analysis focuses on the implementation of inclusive practices for female and early-career researchers in a virtual scientific conference. This organization approach was applied in the XIII Spanish Optical Meeting (RNO2021), which was also characterized by avatars interacting in an online metaverse. The effectiveness of inclusive policies and novel technological tools was evaluated using the participation data and a post-conference survey. Our study reveals the high impact of inclusive actions and a strong interest in the scientific community to explore conference advances.

Chaudry Sajed Saraj, Subhash C. Singh, Gopal Verma et al.

Transition–metal-doped electrocatalysts are considered as low-cost alternatives of Pt and RuO2 electrocatalysts for large scale electrochemical generations of hydrogen and oxygen, respectively. Although, chemical synthesis, typically adopted to produce these electrocatalysts, is scalable but hazardous by-products and chemical wastes create growing environmental concerns. Here, we developed a single step, single pot, and environmentally friendly physical approach of electric field-assisted pulsed laser ablation in liquid for the synthesis of colloidal solution of pure CuMoO4 (CMO) electrocatalysts. The entire process took few minutes and did not involve or generate any chemical. A pulsed picosecond laser was used to ablate MoS2 target at the solid-liquid interface to generate spatially confined plasma plume. Two parallel electrodes (copper sheets) were mounted around the plasma plume to modulate the plasma parameters, control the reactions at the plasma-liquid interface, and simultaneously inject copper ions from the electrode to the laser-produced plasma (LPP) for the generation of CMO. nanoparticles. Surprisingly, we observed that by varying the applied electric field, we can efficiently control the size, shape, crystallinity, morphology, and composition of as produced CMO nanocomposites and enhance their hydrogen evolution reaction (HER) performance. The characterization results proves that the introduction of applied electric field during the laser ablation process significantly change the morphology of as-prepared nanomaterials, and the shape of these nanomaterials were spherical, spindle and cuboid for MoS2, CuO and CMO respectively. Among all the fabricated electrocatalysts, CMO-60 is the best HER performer in alkaline medium, while MoS2 and CuO nanoparticles were the worse. For CMO-60 sample, only 440 mV overpotential required to reach the current density of 10 mA/cm2 and as well as posess good stability. We found that electrocatalysts produced at a higher electric field have higher contents of copper and oxygen leading to a superior HER activity. The developed approach can be applied for the synthesis of other electrocatalysts for a range of chemical reactions.