Light Phenomena Research Articles

Influence of Light of Different Spectral Compositions on Growth Parameters, Photosynthetic Pigment Contents and Gene Expression in Scots Pine Plantlets.

The photoreceptors of red light (phytochromes) and blue light (cryptochromes) impact plant growth and metabolism. However, their action has been barely studied, especially in coniferous plants. Therefore, the influence of blue (maximum 450 nm), red (maximum 660 nm), white light (maxima 450 nm + 575 nm), far-red light (maximum 730 nm), white fluorescent light and dark on seed germination, growth, chlorophyll and carotenoid contents, as well as the transcript levels of genes involved in reception, photosynthesis, light and hormonal signaling of Scots pine plantlets, was investigated. The highest values of dry weight, root length and photosynthetic pigment contents were characteristic of 9-day-old plantlets grown under red light, whereas in the dark plantlet length, seed vigor, seed germination, dry weight and pigment contents were decreased. Under blue and white lights, the main studied morphological parameters were decreased or close to red light. The cotyledons were undeveloped under dark conditions, likely due to the reduced content of photosynthetic pigments, which agrees with the low transcript levels of genes encoding protochlorophyllide oxidoreductase (PORA) and phytoene synthase (PSY). The transcript levels of a number of genes involved in phytohormone biosynthesis and signaling, such as GA3ox, RRa, KAO and JazA, were enhanced under red light, unlike under dark conditions. We suggest that the observed phenomena of red light are the most important for the germination of the plantlets and may be based on earlier and enhanced expression of auxin, cytokinin, gibberellin and jasmonate signaling genes activated by corresponding photoreceptors. The obtained results may help to improve reforestation technology; however, this problem needs further study.

Efficiency enhancement of natural cocktail dyes in a TiO2-based dye-sensitized solar cell and performance of electron kinetics on the TiO2 surface

In this study, natural dye extracts were prepared from the dried leaves of Andrographis paniculata and Psidium guajava (APPG). The study’s objective was to increase the light harvesting phenomenon from solar energy utilizing natural dye from APPG, and the problem statement was to harvest the optimum solar radiation and convert it into electrical energy. Acetone and ethanol were used as solvents during the preparation process. Based on this research, the crystallite size of TiO2 nanoparticles was assessed, the impact of acetone and ethanol on APPG dye was compared, and the absorption, FTIR, and UV-Vis spectra of the solar cell fabrication process using solvents were experimentally explored. APPG leaf extract functions as a dye sensitizer. Cells are precisely sandwiched with a photoanode, TiO2 nanoparticles, an electrolyte (I/I3−), and a cathode. The JV properties of dye extracts utilizing acetone and ethanol were measured using a solar simulator equipped with a 100 mW/cm2 Xenon light and a Keithley 2400 Graphical Series SMU. An experimental DSSC with dye extraction and utilizing acetone solvent yielded a maximum photo-conversion efficiency of 0.6914%, while ethanol yielded a photo-conversion efficiency of 0.5630%. Furthermore, an energy-level diagram was used to explain the electron kinetics of DSSC, and the time required for transfer electron injection in the TiO2 surface from a dye-excited state was 150 ps.

Perspective on 3D vertically-integrated photonic neural networks based on VCSEL arrays

Abstract The rapid development of artificial intelligence has stimulated the interest in the novel designs of photonic neural networks. As three-dimensional (3D) neural networks, the diffractive neural networks (DNNs) relying on the diffractive phenomena of light, has demonstrated their superb performance in the direct parallel processing of two-dimensional (2D) optical data at the speed of light. Despite the outstanding achievements, DNNs utilize centimeter-scale devices to generate the input data passively, making the miniaturization and on-chip integration of DNNs a challenging task. Here, we provide our perspective on utilizing addressable vertical-cavity surface-emitting laser (VCSEL) arrays as a promising data input device and integrated platform to achieve compact, active DNNs for next-generation on-chip vertical-stacked photonic neural networks. Based on the VCSEL array, micron-scale 3D photonic chip with a modulation bandwidth at tens of GHz can be available. The possible future directions and challenges of the 3D photonic chip are analyzed.

Thermal, Lighting and IAQ Control System for Energy Saving and Comfort Management

The present work proposes a simulation and control framework for home and building automation, focusing on heating, ventilating, and air conditioning processes. Control systems based on different advanced control architectures and different control policies are simulated and compared, highlighting control performances, and energy-saving results in terms of CO2 emissions reduction. Heat, lighting, and natural ventilation phenomena were modelized through first-principles and empirical equations, obtaining a reliable and flexible simulation framework. Energy-consuming and green energy-supplying renewable sources were integrated into the framework, e.g., heat pumps, artificial lights, fresh air flow, and natural illuminance. Different control schemes are proposed, based on proportional–integral–derivative advanced control architectures and discrete event dynamic systems-based supervisors; different control specifications are included, resulting in a multi-mode control system. The specifications refer to energy savings and comfort management, while minimizing overall costs. Comfort specifications include thermal comfort, lighting comfort, and a good level of indoor air quality. Simulations on different scenarios considering various control schemes and specifications show the reliability and soundness of the simulation and control framework. The simulated control and energy performances show the potential of the proposed approach, which can provide energy-saving results greater or equal to 6 [%] (in each season) and 19 [%] (in one year) with respect to more standard approaches.

Between Poetics and Theology: “The Second space” by Czesław Miłosz

The artistic structure of Czesław Miłosz’s book “The Second Space” is analyzed in the context of the poet’s religious and philosophical worldview. It is argued that the dialectics of the “first” and “second space” is revealed in the book through a special “language” of analogies between the spiritual and bodily, heavenly and earthly, male and female, so the theory of Swedenborg and the ideas of Oskar Miłosz have a conceptual significance for the worldview context. The system of analogies is a symbolic “code”, in which the central role is played by the biblical story of human origin. The image of “first” space is shown through a combination of rituals and object realities. The concept of “second space” is associated with the phenomenon of light therefore the author refers to Oscar Miłosz’s hypothesis of the origin of the universe through a flash. The image of the “second space” is not wholly speculative, it has to do with the sensory – visual, auditory, olfactory, tactile and gustatory. The dialectic of analogies between the earthly and the heavenly is revealed through the poetics of epiphanies, understood as “privileged moments” and destined to comprehend “essential reality”. Genre elements of prayer are connected to the concepts of “first” and “second space”, to the poetics of analogies and epiphanies. However, “prayer” poems often become a manifestation of the poet’s contradictory nature, in the consciousness of which the thesis of the necessity of the “second space” collides with doubts about its reality.

DEČJE MISKONCEPCIJE O SVETLOSNIM FENOMENIMA

In the context of the subjects World around us and Nature and Soci- ety, numerous complex and abstract natural phenomena are studied, which students often misinterpret. The first step in these teaching situations is gaining a deeper insight into the meaning and sources of such naive beliefs. The aim of this research was to investigate misconceptions of students from the first to the fourth grade of elementary school about light phenomena such as sources and propagation of light, nature of sight, transparency of materials, reflection and refraction of light, and shadows, through interviews. Conversa- tions with 24 students, six from each grade, from three elementary schools in Sombor and the surrounding area, were recorded and transcribed. Students’ responses were classified based on similarities and categorized as spontaneous, mixed, “I don’t knowˮ, and scientific. The results indicate the presence of a large number of diverse misconceptions about the examined concepts regardless of the students’ age. Specifically, students often define light based on visible effects it creates (glowing, sparkling, shining) as opposed to darkness (il- luminating darkness, which is not dark), by listing examples of light sources (fire, the Sun, light bulbs, car headlights), and through incomplete descriptions of its nature (source of energy, heat, or life). Widespread misconceptions were also confirmed, such as the Moon being a source of light, light “existingˮ only in sources and on illuminated surfaces (light cannot pass through the air because..., it cannot pass through water because...), and some objects (white paper, fluorescent vest) being visible without light. Unlike the concept of material transparency, which is clear to most students, understanding the formation and characteristics of shadows (shape, position, size, and number) as well as the phenomena of reflection and refraction of light is much more challenging. It can be concluded that within the context of predominantly traditionally designed teaching practices, concept of light represents a significant challenge for younger students. To introduce these and similar concepts correctly into students’ system of concept, adequate and effective teaching ap- proaches are necessary, taking into account children’s misconceptions, the detection of which is also facilitated by this research.

АПОФАТИКА РУССКОЙ КУЛЬТУРЫ: ТРАДИЦИИ СКОМОРОШЕСТВА В СТИХОТВОРЕНИИ С.А. ЕСЕНИНА «Я ОБМАНЫВАТЬ СЕБЯ НЕ СТАНУ…»

The object of the article is the tradition of buffoonery in Russian culture. The subject of the research is the ambivalent image of dusk, the phenomenon of twilight in Russian poetry, which is associated with inverted reality, the antithetic world. The material for this article is represented by the creative heritage of S.A. Yesenin who is rightfully considered to be one of the best folklore poets of the early 20th century. The cultural-philosophical analysis is centred on a poem from the cycle “Moskva Kabatskaya” [Moscow of Taverns], namely “I will not deceive myself...”. This poem is internally structured according to the principle of interaction between two types of reality in art – the phenomenal and the noumenal, the rational and the spontaneous. Much attention is paid to the problem of transformation of the buffoonery tradition in the poet’s works, the latter being associated with the image of murky heart, nocturnal light denoting the inverted reality, the ritual chaos. The paper explores the phenomena of gloom, of vespertinal and unfading light which are linked with the antithetic world, i.e. with inverted reality and the thanatological text of culture. The research methodology involves the holistic ontological-hermeneutic analysis of S.A. Yesenin’s poetic texts. The research results may be of interest for philologists tending to include literature in the space of a great dialogue of cultures and may also be used in courses on cultural studies and Russian philosophy.

Securing Data in Multimode Fibers by Exploiting Mode-Dependent Light Propagation Effects.

Multimode fibers hold great promise to advance data rates in optical communications but come with the challenge to compensate for modal crosstalk and mode-dependent losses, resulting in strong distortions. The holographic measurement of the transmission matrix enables not only correcting distortions but also harnessing these effects for creating a confidential data connection between legitimate communication parties, Alice and Bob. The feasibility of this physical-layer-security-based approach is demonstrated experimentally for the first time on a multimode fiber link to which the eavesdropper Eve is physically coupled. Once the proper structured light field is launched at Alice's side, the message can be delivered to Bob, and, simultaneously, the decipherment for an illegitimate wiretapper Eve is destroyed. Within a real communication scenario, we implement wiretap codes and demonstrate confidentiality by quantifying the level of secrecy. Compared to an uncoded data transmission, the amount of securely exchanged data is enhanced by a factor of 538. The complex light transportation phenomena that have long been considered limiting and have restricted the widespread use of multimode fiber are exploited for opening new perspectives on information security in spatial multiplexing communication systems.

Atmospheric plasmas research linked to electromagnetic signals and earthquakes

This paper presents the outcome of monitoring aimed at studying seismic precursor candidates with a multi-parameter system, carried out at a Science Camp in July 2022 in the northwestern Italian Apennines, in the province of Parma. Pre seismic signals, closely related to the preparatory stages of an earthquake, were detected with a crustal diagnosis, based on physical signals, generated by tectonic stress. The instrumental results show a potential temporal concatenation, which describe, at the level of hypothesis, the phases of the ongoing tectonic stress. The model followed Zou’s theories who which associate the formation of plasmas in the atmosphere with the piezoelectricity of rocks under stress. According to his model, rocks placed under tectonic stress and in the presence of moisture can produce both charged particles and radio electromagnetic waves, at high and low frequencies. A spherical plasmoid would originate from this combination as a wave-particle interaction effect. According to Teodorani’s description High-Frequency radio waves-particularly microwaves-would heat and ionize the surrounding air, while low-frequency waves, particularly Very Low Frequencies and Extremely Low Frequency, would help condense the plasma, which in turn would immediately go into swirling motions within it, until it formed the «self-contained» structure seen in the sky as a light phenomenon. Monitoring, therefore, involved the detection of low-frequency waves preceding plasmas in the atmosphere, directional electromagnetic signals from the Radio Direction Finding (RDF) network, and the occurrence of an earthquake within the 5/6 days’ time window along the same fracture line. A study model that, if confirmed, could be applied to other seismic zones for crustal monitoring.

Analisis Perbandingan Kinerja Antara Sensor Api Flame 5 Channel Dengan Sensor Asap MQ2

Sensors are devices used to detect changes in physical quantities such as light, motion, fire, humidity, temperature, smoke and other environmental phenomena. With the use of sensors, changes in the environment that are detected by the sensor can be seen. Each sensor has a different function but can be used for the same purpose, for example, in detecting a fire. A fire incident can be identified by two things, namely the presence of fire or smoke, but it cannot be known whether it is fire or smoke first which is easy to detect from the fire. Therefore it is necessary to do a sensor performance comparison test which aims to find out which sensor detects fire earlier. This study uses a quantitative two-sensor test comparison method. The two sensors, namely the Flame 5 Channel fire sensor, have a function to detect fire which will be tested with the time parameter needed to detect fire based on the distance and the fan's time requirement to turn off the fire. Then the MQ2 sensor has a function to detect smoke based on its thickness which will be tested with the estimated time parameter for the thickness of the smoke until the sensor detects it based on the distance and time it takes for the smoke to disappear using a fan. The results of this study are a comparison of the two sensor tests to become a recommendation for the use of sensors in detecting fires.

Super diffraction limit spectral imaging detection and material type identification of distant space objects.

The image information of distant objects shows a diffuse speckle pattern due to diffraction limit, non-uniform scattering, etc., which is difficult to achieve object discrimination. In this study, we have developed a staring spectral video imaging system mounted on a ground-based telescope observation platform to detect the high orbit space objects and gain their spectral images for six groups of GEO targets. The speckle remains basically the same characteristic as the projection structure of the object due to "the balloon inflation phenomenon of near parallel light during long-distance atmospheric transmission" under the premise of considering the bi-directional reflection distribution function (BRDF), Rayleigh scattering theory, and the memory effect. Based on this phenomenon, a mathematical model of remote target scattering spectrum imaging is established where the speckle can be treated as both a global speckle and speckle combination of texture blocks caused by various components of the target. The radial basis function (RBF) neural network is separately used to invert the global speckle and the speckle combination of the texture blocks on account of the typical target material database. The results show that the target materials are of relatively fewer kinds in the global inversion with only including gallium arsenide panel (GaAs) and carbon fiber (CF), for which the highest goodness of curve fitting is only 77.97. An improved algorithm makes their goodness of fit reach 90.29 and 93.33, respectively, in view of one conjecture that the target surface contains unknown materials. The spectral inversion result of the texture blocks shows that the types of materials in each target texture block increase significantly, and that the area ratio of different materials inverted in the block is different from each other. It is further confirmed that the speckle image contains the overall projection structure of distant target and the spectral image projection of each component is relatively fixed, which is the result of the comprehensive action of various mechanisms of ultra-long-haul atmospheric transmission and optical system focusing imaging after BRDF spectral scattering. The spectral image fine inversion is expected to restore the clear structure of the target. This discovery provides important support for the remote imaging and identification of distant and ultra-diffractive targets.

Should More Internally Generated Intangible Assets Be Recognized? A Commentary

This study analyzes whether financial statements should recognize more internally generated intangible assets with particular reference to China. This issue is significant because of the increasing importance of the ‘new economy’ and R&D investment, including in China. We present the current accounting requirements for intangible assets and illustrate that the failure to recognize internally generated intangible assets leads to a high ratio of unrecognized value to market capitalization, known as the asset light phenomenon among firms. We discuss and compare international and Chinese views supporting and opposing the recognition of more internally generated intangible assets. We identify and analyze the major issues in general, and in China particularly, that standard setters and their stakeholders have to consider if more internally generated intangible assets are recognized. We focus on areas of recognition, initial and subsequent measurement, and user reaction. We find that the most critical issues are the separability and measurability of internally generated intangible assets. Based on the issues identified, we discuss initiatives on non‐financial disclosure in relation to unrecognized intangible assets and firms’ value creation. The study elucidates the consequences of current accounting standards on internally generated intangible assets and, by identifying the critical issues, contributes to the debate on whether it is best to adopt recognition of internally generated intangible assets or a disclosure‐only approach.

Analysis of satellite-derived data for the study of fouling in aircraft engines

Atmospheric particulate is one of the main causes of performance degradation in gas turbine engines, especially in the aeronautical field where filter barriers are absent. The ingested particles can stick to the blade surfaces of the engine, varying their shape and roughness. As a consequence, engine performance degradation takes place. The type and the amount of the particles ingested depend on the flight zones and altitude. During their missions, aircrafts follow a prescribed path defined in terms of altitude, longitude, and latitude. During its route, the aircraft engine encounters different environments characterized by different temperature, pressure, and air composition. Regarding the latter issue, the knowledge of this characteristic can be key information when these statistics are needed for obtaining data useful for engine degradation assessment or prediction. Many satellites, such as the environmental satellite CALIPSO, are employed to study the terrestrial aerosol and clouds profile by using a LIDAR (Laser Detection and Ranging). This technology is commonly used to determine the distance between a light emitter and an object and it is based on the light refraction phenomenon. Backscatter coefficients profiles data, which characterize the distribution of particles and aerosols in the atmosphere, are available in the open literature from the findings of CALIPSO. In this work, a new methodology to estimate the aerosol type and concentration encountered by an aircraft during a mission is proposed. To test the feasibility of this method, two aircraft missions for different length scales (medium and long haul) are analyzed and an estimate of the particulate encountered by the engines is provided. The mission analysis has been conducted by discretizing the altitude profile, longitude, and latitude coordinates of each flight and then cross-referencing them with the particulate concentration obtained from CALIPSO data.

A brief review of topological photonics in one, two, and three dimensions

Topological photonics has attracted increasing attention in recent years due to the unique opportunities it provides to manipulate light in a robust way immune to disorder and defects. Up to now, diverse photonic platforms, rich physical mechanisms and fruitful device applications have been proposed for topological photonics, including one-way waveguide, topological lasing, topological nanocavity, Dirac and Weyl points, Fermi arcs, nodal lines, etc. In this review, we provide an introduction to the field of topological photonics through the lens of topological invariants and bulk-boundary correspondence in one, two, and three dimensions, which may not only offer a unified understanding about the underlying robustness of diverse and distinct topological phenomena of light, but could also inspire further developments by introducing new topological invariants and unconventional bulk-boundary correspondence to the research of topological photonics.

Die Rostocker Methode zur qualitativen und quantitativen Bewertung von Intraokularlinsen

For quantitative and qualitative evaluation of the imaging properties of IOLs, axial cross-sectional images can be obtained from the 3-dimensional light distribution by means of an optical bench, as is known from light sheet recordings in fluorescein baths. This paper presents a new image-processing algorithm to enhance the quality of generated axial cross-sectional images, and the two methods are then compared. The 3-dimensional point spread function of a diffractive trifocal IOL (AT LISA tri 839MP, Carl Zeiss Meditec AG, Jena, Germany) was recorded on an optical bench developed in Rostock for different pupil diameters. A specially adapted image processing algorithm was then applied to the measurements, allowing through-focus curves to be generated. In addition, cross-sectional images of the IOLs studied were acquired using the light sheet method in a fluorescein bath. The study clearly shows the superiority of the newly developed method over the light sheet method in terms of image quality. In addition to the individual focal points, fine focal structures as well as halos can be made visible in the cross-sectional images obtained using the new method. In the generated through-focus curves, 3 intensity peaks can be identified, which represent the near, intermediate and far focus of the tested MIOL and cannot be represented by light sheet methods. The interaction of the optical bench with the developed image processing algorithm allows a more detailed understanding of the image formation and false light phenomena of IOLs, which was restricted by the technical limitations of the existing light sheet method. In addition, other quantities such as the through-focus curve can be derived quantitatively.

Light interaction with natural photonic crystal from band gap structure to possible light localization phenomena

Nature exhibited beautiful optical phenomena when the light interacts with special organic materials. Complex natural nanostructures have been unwrapped from age ago to develop specific functions, between them are physics behavior that are waiting to be understood. The structures that conform these natural systems are so sophisticated that in our time they are the reason to start research work in this new field of knowledge, it implies the combination of scientific knowledge from diverse areas. Here, we start our study with the optical and structural characterization of the wing samples of Quesada gigas, Greta oto, and Morpho cypris. There are three native species from South America that exhibit structural color on the surface of their wings known as iridescence, this optical effect is attributed to photonic structure arrays inside the samples [1] (Vukusic and Sambles, 2003). Our focus in this work is to understand how the structural disorder influences the light interaction with the natural photonic systems. In order to obtain this goal, interferometric measurements using spatiotemporal resolution were done, and experimental and computational methods were implemented too. Our results offer promissory evidence for the light localization in natural photonic systems when structural disorder is present in the studied system. Therefore, in this work we suggest one way to detect light localization in natural photonic structures with the purpose to establish a correlation between optical effect and structural array in natural systems.

The wave theory of light gives better explanations for key phenomena in physics

The well-known wave property of destructive superposition can be used to explain continuous radiation from bound electrons in hydrogen, without quantized energy and quantum jumping. The wave model can be used to explain the most important phenomena in light, without quantization of light. The ether concept can be used to explain the cosmological red shift, without any need for using the Big Bang model.

Ge Microcrystals Photedetectors with Enhanced Infrared Responsivity

he direct epitaxial growth of germanium on silicon (Ge-on-Si) has fostered the development of near infrared detectors for telecom and imaging applications [1]. The long wavelength responsivity of these devices is limited to approximately 1550 nm corresponding to the direct energy gap of Ge EgΓ= 0.8 eV. Indeed, the absorption coefficient at the indirect gap EgL= 0.66 eV (λ≈1800 nm) is roughly two orders of magnitudes lower than that above the direct gap threshold. A sizable absorption within the 1550-1800 nm windows would, therefore, require exceedingly thick epilayers leading to wafer bowing and crack formation. An extended infrared absorption would, however, be beneficial for imaging applications since long wavelength radiation is less affected by Rayleigh and Mie scattering limiting visibility in fog and dusty conditions.A viable route to enhance the responsivity of Gen-on-Si photodetectors in the 1550-1800 nm region might be exploiting the micro-structuring of the absorbing layer to increase the effective volume of interaction between light and matter.In this work we report on a new type of detector, obtained from Ge micro-crystals epitaxially grown on a patterned Si substrate [2]. The faceted morphology and relatively high aspect ratio of the microcrystals is seen to enhance the detector responsivity in the wavelength region comprised between the direct (λ≈1550 nm) and indirect (λ≈1800 nm) gap of Ge, as compared to conventional planar devices.The epitaxial growth has been performed by means of Low-Energy Plasma-Enhanced CVD (LEPECVD). Microcrystal formation is based on the self-assembly of Ge crystals on a Si substrate, deeply patterned by optical lithography and reactive ion etching. 3D microcrystals, several micrometer tall and characterized by a limited lateral expansion, are obtained by using optimized growth parameters. Due to crystal faceting, light trapping effects are expected to take place within the microcrystals leading to increased in the fraction of absorbed light when compared to conventional epitaxial layers.Modelling of the near-IR absorption properties of the Ge-on-Si micro-crystals, and of conventional epilayer used as a reference,has been performed by finite difference time domain (FDTD) simulations. The ratio between the fraction of absorbed power of an array of Ge-on-Si micro-crystals and a planar Ge-on-Si epilayer is estimated to be always higher than one, with a factor of two increase in the spectral region between the direct and indirect gap (λ≈1550-1800 nm).Ge microcrystals photodetectors have been fabricated using graphene as a transparent top contact (see Fig. 1). A confocal microscope with a supercontinuum laser source (1300 - 1800 nm), has been used to obtain the photodetector responsivity. The spot size was smaller than the patterned area (100 μm x 100 μm) thus enabling the illumination of a few Ge-on-Si micro-crystals. The photocurrent measurements experimentally confirm the enhanced absorption in the 1550-1800 nm spectral region [4] with a responsivity exceeding, by a factor of seven, that of a reference conventional Ge-on-Si photodiode at 1700 nm.These results pave the way to a new class of photodetectors, exploiting light trapping phenomena in self assembled semiconductors microstructures. J. Michel, J. Liu, and L. C. Kimerling, High-performance Ge-on-Si photodetectors, Nat. Photonics 4, 527–534, (2010)C. V. Falub et al., Scaling Hetero-Epitaxy from Layers to Three-Dimensional Crystals, Science (80). 1330–1334, (2012).M. Albani et al. Faceting of Si and Ge crystals grown on deeply patterned Si substrates in the kinetic regime: phase-field modelling and experiments, Scientific Reports 11, 18825 (2021)V. Falcone et al., Graphene/Ge microcrystal photodetectors with enhanced infrared responsivity, APL Photonics 7, 046106 (2022) Figure 1

Twisted Light in a Single‐Crystal Fiber: Toward Undistorted Femtosecond Vortex Amplification

AbstractIntense femtosecond optical vortices with spatially structured amplitude and spiral phase front give rise to novel phenomena in light–matter interactions and strong‐field physics. However, current femtosecond vortex sources exhibit a poor power handling capability and amplification remains an open challenge due to a number of inherent technical difficulties. Here, it is demonstrated that a single‐crystal fiber laser amplifier is particularly well‐suited to directly amplify a femtosecond optical vortex without pulse stretching and compression in the time domain, while still maintaining the spatial properties associated with a clear central singularity and a spiral phase front, i.e., a well‐defined amount of orbital angular momentum (OAM).The optical nonlinearity experienced by such twisted light is verified to be substantially weaker compared to a fundamental mode beam where supercontinuum generation and spatial distortion are observed. The simple design and straightforward power scaling capability pave the way toward ultrahigh‐intensity femtosecond singular laser sources with an arbitrary topological charge. Such ultrafast OAM light sources are expected to help reveal complex physical phenomena in light–matter interactions and expand the applications to attoscience with X‐ray vortices, laser plasma acceleration, and micromachining.

“Who is Bright is Holy”: Situation of Light Designation in Akathists to Russian Saints

The results of a study of the situation of light designation in akathists to Russian saints is presented in the article. The relevance of studying the phenomenon of light on this material is due, firstly, to the most important text-forming role of light designs in this hymnographic genre, and secondly, to the need for an in-depth study of the role of the verb in the organization of the Slavic sentence. The situation of light designation became the direct object of analysis, and the participants in this situation became the subject. The focus of research attention is on the relevant valence (semantic and syntactic) characteristics of the verb as the structural center of the sentence. The main research methods were: functional-semantic, contextual analysis of lexical units, statistical. As a result of the study, a linguistic corpus of light designations (3,157 units) was identified, their part-of-speech affiliation was characterized, a chronological distribution was demonstrated, and the dominant root-forming elements (svet-, siya-, zar-, blist-, svesh-) were established. Particular attention is paid to the grammatical mechanisms that provide light designation, as well as to its direct participants. The emphasis is on the main participant — the light. The description of the register of possible semantic roles of participants in the situation of light designation (Subject, Object and their subtypes) is focused on the division traditional in the Orthodox metaphysics of light: “uncreated light”, “smart light” and “sensual light”.