bluuebunny/crossref_metadata_2025 huggingface dataset:
Abundance and physical factors affecting the appearance of selected terrestrial birds in Khao Yai National Park using camera trapping
Authors: Kanka Pemika , Sukmasuang Ronglarp , Duengkae Prateep , Siripattaranukul Kittiwara
Published: February 2023

Abstract. Kanka P, Sukmasuang R, Duengkae P, Siripattaranugul K. 2023. Abundance and physical factors affecting the appearance of selected terrestrial birds in Khao Yai National Park using camera trapping. Biodiversitas 24: 222 232. This study used results from camera traps set for Dhole (Cuon alpinus) and their prey during 2017-2020 in Khao Yai National Park to assess the species richness of ground-dwelling birds and identify abundance and also temporal appearance of the species in the area. We selected only the Pheasant species that typically forage on the ground to investigate the physical factors affecting the appearance in Khao Yai National Park. Based on camera trapping data with a total of 4139 trap days, 115 camera locations showed 36 species of birds belonging to 21 families, and 13 orders of ground-dwelling bird species were recorded. Siamese Fireback (Lophura diardi), Red Junglefowl (Gallus gallus), and Silver Pheasant (Lophura nycthemera) were detected with an abundance index of 10.65%, 7.27%, and 1.84%, respectively. The ground-dwelling bird abundance index from the camera traps accounted for 26.85% of the total fauna. Although the Phasianidae were found to be diurnal species, this study also shows a statistically significant difference in the average time between Red Junglefowl and Siamese Fireback. Meanwhile, there was no statistically significant difference between Red Junglefowl and Silver Pheasant during their active time. The water sources showed a significant effect on the presence of the Siamese Fireback in data analysis; however, no physical environmental factors significantly affected the distribution of Red Junglefowl and Silver Pheasant. This study found that surrounding creeks and streams significantly impacted the appearance of the Siamese Fireback. As a result, area management needs to prevent and reduce disturbances along a creek in order to effectively manage the habitat of the Siamese Fireback and other wildlife.
Composition and diversity patterns of weeds in herbicide tolerant maize fields and margins in the Eastern Cape, South Africa
Authors: KWINDA MURENDENI , SIEBERT STEFAN JOHN , VAN COLLER HELGA , MASEHELA TLOU SAMUEL
Published: February 2023

Abstract. Kwinda M, Siebert SJ, Coller HV, Masehela TS. 2023. Composition and diversity patterns of weeds in herbicide tolerant maize fields and margins in the Eastern Cape, South Africa. Biodiversitas 24: 399-414. Weeds are considered undesirable plants that grow where they are not wanted, as they often outcompete crops and other beneficial species. This study aimed to compare species composition and diversity of weedy plant communities in fields planted with herbicide tolerant maize and associated field margins in the Eastern Cape Province, South Africa. A total of 88 weed species, representing 31 families were recorded from 244 plots for maize fields and field margins combined. The maize fields and margins across the four sites shared 53% of species. Non-metric Multidimensional Scaling grouped maize fields and field margins separately based on weed species composition. Moreover, maize fields and margins differed significantly in terms of Simpson (p=0.044) and Shannon indices (p=0.003), with diversity being higher in the fields. This study confirms that maize fields have a dissimilar composition of weedy species and dissimilar diversity, which differs from those of field margins. This result enables farmers to know whether current herbicide use is sufficient for targeted weed control. The findings and knowledge will benefit maize farmers and future researchers working on weeds in Sub-Saharan Africa when it comes to the development, implementation, and prioritization of various herbicide-based weed management protocols to ensure maximum crop productivity.
Molecular and morphological characterization of fungi isolated from nutmeg (Myristica fragrans) in North Sulawesi, Indonesia
Authors: ARIFAH FITRI , AINI LUQMAN QURATA , MUHIBUDDIN ANTON
Published: February 2023

Abstract. Arifah F, Aini LQ, Muhibuddin A. 2023. Molecular and morphological characterization of fungi isolated from nutmeg (Myristica fragrans) in North Sulawesi, Indonesia. Biodiversitas 24: 441-453. Nutmeg (Myristica fragrans Houtt) is one of the predominant commodities from Indonesia exported to the EU market. However, it is frequently rejected due to mycotoxin (especially aflatoxin) content exceeding the aflatoxin standard set by the EU. The high levels of aflatoxin were hypothesized to be produced by a toxigenic fungus infecting nutmeg during and after harvest. The study aims to determine and identify fungal contaminants in nutmeg kernels and provide information on the types of mycotoxins produced. Ten fungal morphotypes were isolated from nutmeg kernels collected from North Minahasa, North Sulawesi, Indonesia, and were grouped into four genera (Aspergillus, Lasiodiplodia, Rhizopus, and Penicillium) based on morphological characters. Ten fungal morphotypes were identified, i.e., Aspergillus flavus (Groups I and II), A. tamarii (Groups I and II), A. niger, A. aculeatus, A. ochraceus, Lasiodiplodia sp., Rhizopus delemar, and Penicillium sp. Isolates of A. flavus and A. tamarii were divided into two groups based on slight differences in their colony appearances. Molecular identification using homology of 18S rDNA sequences and ITS regions supports morphological identification except for isolates of A. flavus (Groups I and II), Lasiodiplodia sp., and Penicillium sp. These isolates were identified as A. nomiae and A. aflatoxiformans (A. autswikcii), L. theobromae, and P. citrinum. The maximum likelihood phylogenetic tree showed that isolates from the same species were grouped in the same clade. The L. theobromae was the most dominant type of fungus in the nutmeg kernels (55.61%), followed by A. niger (23.8%) and A. tamarii (10.53%). It is the first report of A. aflatoxiformans or A. autswikcii in nutmeg kernels, and no incidence of L. theobromae in nutmeg kernels from Indonesia previously.
Antibacterial activity of ethanol extract of banana, cassava, and pineapple peels against a fish pathogen Aeromonas hydrophila
Authors: MULIA DINI SISWANI , RAICHA RAIH , LUNGGANI CITRA PUSPANING , ERINA SISKA NUR , WULIANDARI JULI ROCHMIJATI , PURBOMARTONO CAHYONO , ISNANSETYO ALIM
Published: February 2023

Abstract. Mulia DS, Raicha R, Lunggani CP, Erina SN, Wuliandari JR, Purbomartono C, Isnansetyo A. 2023. Antibacterial activity of ethanol extract of banana, cassava, and pineapple peels against a fish pathogen Aeromonas hydrophila. Biodiversitas 24: 481-485. Aeromonas hydrophila is the most virulent bacteria for almost all freshwater fish species. One method to control pathogenic bacteria in fish should be safe and environmentally friendly, including utilizing natural wastes such as banana peels (Musa paradisiaca), cassava peels (Manihot esculenta), and pineapple peels (Ananas comosus). These natural wastes contain bioactive compounds. Their utilization increases the waste value. This study aims to determine the potential of banana peel, cassava peel, and pineapple peel waste as an antibacterial against A. hydrophila, a causing agent of Motile Aeromonas Septicemia (MAS) in freshwater fish. Parameters observed included phytochemical compounds, MIC, and MBC values of banana, cassava, and pineapple peels. Phytochemical screening was performed using thin-layer chromatography (TLC) and foam test. The microdilution method carried out the antibacterial activity of banana peel, cassava peel, and pineapple peel against A. hydrophila. It determines the minimum inhibitory concentration (MIC); and the minimum bactericidal concentration (MBC) values. Phytochemical screening results showed that banana, cassava, and pineapple peel extracts contained flavonoids, alkaloids, terpenoids, tannins, and saponins. The MIC values of banana peel, cassava peel, and pineapple peel extract were 600, 400, and 200 µg/mL, respectively. The MBC values of banana peel, cassava peel, and pineapple peels were 4 × MIC, 2 × MIC, and 1 × MIC, respectively. Extract of pineapple peel exhibited better antibacterial activity than banana and cassava peels. However, the three waste extracts indicated the antibacterial potential to be developed as natural bactericides to control A. hydrophila bacterial disease.
Morphological characteristics and biodiversity of mudskipper fish (Periophthalmus: Gobiidae) in mangrove ecosystem of coastal Bay of Tomini, Boalemo, Gorontalo Province, Indonesia
Authors: Baderan Dewi Wahyuni K. , Aydalina Regina Valentina , Hamidun Marini Susanti
Published: February 2023

Abstract. Baderan DWK, Aydalina RV, Hamidun MS. 2023. Morphological characteristics and biodiversity of mudskipper fish (Periophthalmus: Gobiidae) in mangrove ecosystem of coastal Bay of Tomini, Gorontalo Province, Indonesia. Biodiversitas 24: 498-507. The southern sea area of Gorontalo Province is part of Tomini bay, the biggest bay in Indonesia. This area has a unique biodiversity and is Sulawesi endemic. The mangrove forest in the coastal bay of Tomini Boalemo is one of the habitats for flora and fauna, a place for spawning, nurturing, and food hunting for fish. The mudskipper is a fish that lives in the mangrove area. This study aims to reveal the morphological characteristics and biodiversity of mudskipper (Periophthalmus: Gobiidae) in the ecosystem of Tomini Boalemo coastal bay of Gorontalo Province. This study employed a quantitative descriptive that also implemented purposive sampling as the sampling method in three ecosystem stations of Tomini Boalemo coastal bay (Dulupi, Bajo, and East Pentadu mangrove). The mudskippers were collected manually when the water was receding using a fish net. The sample which had been collected were then identified based on 22 morphological, 24 morphometric, and seven meristic characteristics. The identification results were then compared with the identification key. The mudskippers' species were then analyzed to determine the species' biodiversity (diversity, evenness, species richness, and dominance indexes). The research result revealed five species from Periophthalmus Genus: Periophthalmus argentilineatus, Periophthalmus kalolo, Periophthalmus malaccensis, Periophthalmus minutus, Periophthalmus variabilis, with total individuals 561. The score of H?: 1.09 showed that the diversity of mudskipper fish was categorized as medium. The evenness index was 0.99 obtained from 3 observation stations, while the lowest dominance index was on station II with a score of 0.34, and the score of R1 in each station was respectively (0.19); (0.36); and (0.2). The results of this study could be used as a database for the sustainable management of Tomini Bay to tackle the threats of species extinction through aquatic life protection and preservation to arrange the natural balance and support the availability of the coastal resource for future generations.
Utilization of farmer priority on local beef cattle development strategy in Central Java, Indonesia
Authors: Agustine Restiyana , Muzayyanah Mujtahidah Anggriani Ummul , Putra Ahmad Romadhoni Surya , Baliarti Endang
Published: February 2023

Abstract. Agustine R, Muzayyanah MAU, Putra ARS, Baliarti E. 2023. Utilization of farmer priority on local beef cattle development strategy in Central Java, Indonesia. Biodiversitas 24: 508-515. Indonesian local beef cattle, Peranakan Ongole (PO), is essential cattle breed predominantly raised by smallholder farmers in Central Java Province. Although it is generally perceived that raising PO cattle is not a regular source of income for the majority of farmers, however, there are few specific studies investigating the aspects and motives of farmers to keep their cattle. Therefore, this study is designed to explore the perspective of farmers leaders in Central Java, Indonesia, toward the priority aspects of raising PO cattle for their livelihoods. We selected Blora, Klaten, Grobogan, and Rembang as representatives of the study involving 29 farmers leaders with at least ten years of experience. Analytic Hierarchy Process was employed as a decision-making instrument to understand better various aspects used by PO cattle farmers. The results show that farmers consider investment function as their primary goal in raising PO cattle in all study areas. Then, farmers consider reproduction performance as the top priority aspect. In conclusion, the study revealed that smallholder farmers consider reproductive ability as a priority due to farmers make the investment function the main goal in raising PO cattle. Therefore, we recommended that farmers improve their knowledge regarding cows' reproduction through extension workers' assistance. Certainty on the PO cattle's selling price is needed so that raising PO cattle is feasible as an investment and stimulates the interest of farmers raising PO cattle.
Detection of multidrug-resistant (MDR) Staphylococcus aureus and coagulase-negative staphylococci (CoNS) in cow milk and hands of farmers in East Java, Indonesia
Authors: KHAIRULLAH ASWIN RAFIF , KURNIAWAN SHENDY CANADYA , SUDJARWO SRI AGUS , EFFENDI MUSTOFA HELMI , AFNANI DANIAH ASHRI , SILAEN OTTO SAHAT MARTUA , PUTRA GIOVANNI DWI SYAHNI , RIWU KATTY HENDRIANA PRISCILIA , WIDODO AGUS , RAMANDINIANTO SANCAKA CHASYER
Published: February 2023

Abstract. Khairullah AR, Kurniawan SC, Sudjarwo SA, Effendi MH, Afnani DA, Silaen OSM, Putra GDS, Riwu KHP, Widodo A, Ramandinianto SC. 2023. Detection of multidrug-resistant  Staphylococcus aureus and coagulase-negative staphylococci in cow milk and hands of farmers in East Java, Indonesia. Biodiversitas 24: 658-664. Cow milk is a nutrient-dense food containing various nutrients, i.e., carbohydrates, fat, and protein. However, it can potentially spread several pathogenic bacteria, such as staphylococci. Staphylococci cause public health problems. Staphylococcal strains were divided into two groups based on coagulase characteristics, namely coagulase-positive and coagulase-negative staphylococci (CoNS). Coagulase-positive was represented by Staphylococcus aureus. S. aureus and CoNS can become resistant to several antibiotics, known as multidrug resistance (MDR) bacteria. S. aureus and CoNS bacteria are known as causal agents in human infections. This study aims to identify the presence of multidrug resistance S. aureus and CoNS bacteria in several dairy farms in East Java, Indonesia. We collected 332 milk and 125 swab samples from the hand of farmers from several dairy farms in Probolinggo, Tulungagung, and Blitar of East Java, Indonesia. The collected S. aureus and CoNS were tested for antibiotic susceptibility using the disc diffusion method. The antibiotic used were cefoxitin, erythromycin, gentamicin, tetracycline, and oxacillin. The results of isolation and identification based on morphological and biochemical characteristics showed that out of 457 samples, 291 samples (63.68%) were positive for S. aureus, and 166 samples (36.32%) were positive for CoNs. There were 15 S. aureus isolates (5.15%) and 7 CoNS isolates (4.22%) confirmed as MDR; therefore, it is confirmed that S. aureus and CoNS resistance to various drugs was very high in the province of East Java. Intensive livestock systems, high livestock densities, and excessive use of antibiotics in modern dairy systems may predispose the developing growth of MDR S. aureus and CoNS infections. In conclusion, the results of this study indicate the presence of very high multidrug resistant S. aureus and CoNS in the East Java provinces. MDR bacteria can be prevented from spreading by improving biosecurity, hygiene in the milking process, and regular health care for animals and dairy workers.
SISTEMA DE AQUISIÇÃO DE DADOS PARA UM DETECTOR DE PARTÍCULAS USANDO UM OSCILOSCÓPIO DIGITAL
Authors: Souza Serafim Elvis Michael , Germano Pinto Guedes
Published: February 2023

A Universidade Estadual de Feira de Santana (UEFS), participa de dois convênios que a incluem na cooperação de grandes projetos na área de detecção de partículas: O primeiro deles é uma colaboração internacional para a construção de um conjunto de 1660detectores de radiação Cherenkov em uma área de 3000 km2.
APLICATIVO “WEB-MOBILE”, DERIVADO DE MÉTODOS DE INTELIGÊNCIA ARTIFICIAL, PARA PREDIÇÃO DE DEFICIÊNCIA DE TESTOSTERONA EM HOMENS
Authors: Nunes Amarante Caroline , Jose de Bessa Junior
Published: February 2023

A testosterona (T) é considerada o hormônio sexual mais importante na fisiologia masculina e tem um impacto significativo nos parâmetros físicos e psicológicos, sendo um importante indicador de boa saúde geral e qualidade de vida. Alguns pacientes podem apresentar deficiência de testosterona (TD), uma condição definida como a presença de níveis séricos baixos persistentes de T e sintomas clínicos Shalender et al. (2010).
Advances in Raman spectroscopy and imaging for biomedical research
Authors: Siddhanta Soumik , Kuzmin Andrey N. , Pliss Artem , Baev Alexander S. , Khare Sunil K. , Chowdhury Pramit K. , Ganguli Ashok K. , Prasad Paras N.
Published: February 2023

Starting with a historical account of evolution in Raman spectroscopy,
in this review we provide details of the advancements that have pushed
detection limits to single molecules and enabled non-invasive
molecular characterization of distinct organelles to provide
next-generation bioanalytical assays and ultrasensitive molecular and
cellular diagnostics. Amidst a growing number of publications in
recent years, there is an unmet need for a consolidated review that
discusses salient aspects of Raman spectroscopy that are broadly
applicable in biosensing ranging from fundamental biology to disease
identification and staging, to drug screening and food and agriculture
quality control. This review offers a discussion across this range of
applications and focuses on the convergent use of Raman spectroscopy,
coupling it to bioanalysis, agriculture, and food quality control,
which can affect human life through biomedical research, drug
discovery, and disease diagnostics. We also highlight how the potent
combination of advanced spectroscopy and machine-learning algorithms
can further advance Raman data analysis, leading to the emergence of
an optical Omics discipline, coined “Ramanomics.”
Finally, we present our perspectives on future needs and
opportunities.
Fifth-Order Analysis of GRIN Lenses
Authors: Marchand E.
Published: February 2023

In any radial gradient the fifth-order differential equation for meridional rays can be given by Here, the following scaling has been adopted: where ℓ is the third optical direction cosine (invariant along any ray) and the prime means d/dt.
Non-Gaussian Imaging Properties and Synthetical Imaging Qualities of Arrays
Authors: Shaomin Wang
Published: February 2023

Non-Gaussian imaging phenomenon of GRIN fiber array was discovered by Rees(1).

On the other hand, some experiments were demonstrated which show how corner-cube arrays have been used to approximate phase conjugation(2-4).

It is possible to find an intrinsic connection between them.

In this report, the imaging properties, pseudo-phase-conjugate properties, synthetical imaging aberrations and optimized design for arrays as compact unit magnification imaging devices are given by means of developed matrix optics.
Design of Medical Endoscopes Using GRIN Optics
Authors: Leiner Dennis C.
Published: February 2023

Rigid endoscopes are widely used instruments for least invasive surgery of various parts of the body, including the abdomen, urinary system, and knee. The rigid endoscope should be distinguished from the flexible fiberoptic endoscope which is generally of larger diameter and is comprised of a two-dimensional array of closely-packed optical fibers. Medical endoscopes using GRIN optics are always rigid endoscopes. The diameter of rigid endoscopes generally range between 1.7mm and 5mm. A typical rigid endoscope may contain up to 50 spherical surfaces. Because of the difficulty in fabricating very small lenses, gradient-index lenses are preferred for the smaller diameter endoscopes.
Gradient Index Lenses Made by Porous Glass Process
Authors: Asahara Y. , Ohmi S.
Published: February 2023

Recently there has been interest in the development of processes for fabricating gradient index (GRIN) lenses, the profile of which is expressed by Here, n0 is the index on the center axis, r is the distance from the center axis and g is the focusing factor. New process, termed "molecular stuffing process" was currently developed for fabricating radially distributed index profiles.[1,2]. This process offers a possibility of making large sized lenses, but there have been no accurate measurements and analyses of their index profiles and aberration characteristics. The purpose of this study is to find the optimum fabrication conditions for parabolic profiles and to evaluate the optical characteristics of lenses made by the molecular stuffing technique.
Plastic Radial-GRIN Rod Lens Prepared by Photocopolymerization
Authors: Ohtsuka Yasuji , Koike Yasuhiro
Published: February 2023

Recently1,2) we developed the plastic radial-GRIN rod with an excellent imaging property throughout the whole lens diameter, by the photocopolymerization of the ternary monomer system. The index distribution of the glass GRIN rod prepared by the ion exchange method3) is limited to the distribution where the refractive index monotonously decreases from center to periphery.
Electron-Beam Written Microlenses
Authors: Nishihara H. , Suhara T.
Published: February 2023

We have proposed micro Fresnel lenses and their fabrication using a computer-controlled electron-beam writing system.1 The lens has the following features: 1) Micro groove patterns can be written to real scale directly and precisely, and therefore the fabrication process is simpler than the case of photolithography. 2) Lenses of different specifications (focal length, wavelength, etc.) can be made only by modifying the computer programs. 3) Since each groove can be optimumly blazed, the diffraction efficiency can be high. Using the technique we have fabricated several kinds of circular and linear microlenses.
Gradient-Index Fiber Optic Components
Authors: Stakelon T. S. , Slick P. I.
Published: February 2023

Micro-optic components using graded-index lenses can provide a wide variety of optical functions for fiber optic applications. For example a lightwave tap and 3-channel wavelength division multiplexer of this type are manufactured by AT&T Technologies, Inc.
Two-Dimensional Device Simulation of InGaAsP Ridge-Waveguide Lasers
Authors: Seki Shunji , Tomizawa Masaaki , Yokoyama Kiyoyuki , Yoshii Akira
Published: February 2023

Two-dimensional device simulator of laser diodes has been introduced and its capability for a quantitative device design of 1.3-µm InGaAsP ridge-waveguide lasers has been shown. It has been quantitatively clarified that the current spreading in the cladding layer plays a key role in determining the threshold current. In addition, it is found that the nonradiative recombination exerts a significant influence not only on the threshold current but also on the carrier distribution in the active layer, that is, the lateral gain profile.
A Quantum-Well Laser Model for Circuit Simulation
Authors: Gao D. S. , Yang A. T. , Kang S. M. , Bryan R. P. , Givens M. E. , Coleman J. J.
Published: February 2023

Circuit simulation models for optical devices are much needed to analyze optical interconnects and properties of optoelectronic integrated circuits. [1] The issue of modeling semiconductor lasers has been addressed by several authors. Previously reported laser models have been mainly for conventional double heterostructure lasers. [2,3,4] However, few adequate models exist for quantum-well lasers. In fact, previous laser models developed for particular device design often fail when the device parameters are changed.
Integrated optical device simulation - an industrial perspective
Authors: Young Terry
Published: February 2023

Although the Beam Propagation and Finite Element Methods (BPM & FEM) are widely used for the analysis of optical devices, they suffer from poor handling of input and output data and are often inflexible. Physical data such as the waveguide structure and associated material parameters must be transformed into a form acceptable to the solver algorithm. A similar interface is required at the other end of the process where a set of numbers must be restructured into a form which the engineer can assimilate. These interfacing functions are known as pre-processing and post-viewing (or post-processing) respectively. Following the example set by other areas of engineering, we have integrated both the FEM and BPM with user-friendly, graphics-based pre- and post-processors, and produced design tools which combine versatility with accuracy and make the numerical techniques accessible to the device engineers.
Comparison of Numerical Studies on Active Rectangular Waveguide Couplers by Vector, Scalar Finite Element, and Effective Refractive Index Methods
Authors: Sakuda Kyohei , Hayakawa Koichi
Published: February 2023

Three different numerical methods, viz., vector, scalar finite element, and effective refractive index methods, are applied to obtain dispersion relations, modal gains and power distributions in active rectangular waveguide couplers. A cross section of a model for numerical studies is shown in Fig.l. Dimensions are given in the figure. Refractive indices are given in Table 1. Typical values of these constants are chosen for III-V compound semiconductors. It is important to understand characteristics of this type of couplers including active waveguide because this is a basic structure of an optical amplifier or a large cavity laser, etc. So far propagation characteristics of active slab waveguide couplers are analyzed, but due to difficulties to apply conventional methods to rectangular active waveguides, it has not been studied thoroughly yet.
Comparison of Numerical Methods for Lightguide Mode Analysis
Authors: Black R.J. , Hénault A. , Pupo V.
Published: February 2023

We provide a CPU-time vs. accuracy comparison as a building-block for choosing among the multitude of numerical methods for wave equation solution (collocation-related, integral equation and shooting). Relative performance depends on both profile and guidance parameter, V. Shooting extrapolation and boundary-matching forms provide refinements for maximum efficiency.
Three Dimensional Nonlinear Interface Simulation
Authors: Regan Jeffrey J. , Andersen David R.
Published: February 2023

A successful technique for simulating the three dimensional nonlinear interface problem is described. Included are discussions of the solution technique, optimization methods used, and a discussion of some preliminary results. Behavior of the three dimensional problem is observed to be quite different from the two dimensional problem which has been investigated recently.
A General Formulation of Transient Forward Raman Scattering
Authors: Blow K.J. , Wood David
Published: February 2023

Transient stimulated Raman scattering (SRS) is traditionally described in terms of a set of quasi-CW waves representing the pump, Stokes and anti-Stokes radiation [1]. There are, however, a number of situations in monomode optical fibres where such a description cannot be applied. Two examples are the secular shift in the frequency of solitons [2], [3], and the soliton-Raman generation of ultrashort pulses [4], [5]. The frequency shift is due to the self interaction of the pump spectrum with its own Raman gain band leading to an overall change of the pulse frequency. The soliton-Raman process starts with a modulation instability of the pump which generates radiation within the Raman gain band, this radiation is then amplified by the Raman band and ultimately fills the spectral region between the pump and Stokes frequencies.
Optimization of Traveling-Wave Integrated-Optic Modulators
Authors: Korotky S. K.
Published: February 2023

Waveguide electrooptic optical modulators and switches, such as those based on LiNbO3, have many potential applications. As the desired modulation and switching frequencies increase, limitations in available drive power and power dissipation demand that these devices operate at the highest possible electrical, as well as optical, efficiency. The tradeoffs faced when designing the waveguides, electrodes, and buffer layer of devices to attain low optical insertion loss and low drive voltage for dc operation are well known [1-3]. For high-speed operation, the traveling-wave mode of operation is preferred because it permits a lower drive voltage for a given bandwidth in comparison to lumped operation. Use of traveling-wave electrodes itself, however, introduces additional tradeoff relationships. These have also been examined quantitatively [3-7], but to date the designer has generally weighed these tradeoffs in a qualitative fashion because the effects of all relevant variables have not been considered within a single computational framework.
Short Pulse Laser Drive of a Supersonic Radiation Front into Solid Matter
Authors: Gumbrell E. T. , Ditmire T. , Smith R. A. , Hutchinson M.H.R.
Published: February 2023

An understanding of energy transport mechanisms is crucial to describing short pulse laser plasma interactions. On progressively longer time scales, electron thermal conduction, hydrodynamic expansion and shock wave propagation are thought to be the principle means by which deposited laser energy leaves the interaction region. Here we report the first observation of a supersonic ionisation front that is faster than any seen so far [1]. This can be explained by a radiative thermal conduction mechanism.
Developments in XUV laser radiography of laser driven targets
Authors: Key M H , Kalantar D H , Nilson J , Remington B A , Weber S V , Wolfrum E , Neely D , Rose S J , Zhang J , Kim N S , Wark J S , Lewis CLS , Mac Phee A G , Warwick J , Demir A , Lin J , Smith R , Tallents G J
Published: February 2023

XUV lasers are being exploited for radiography with high space, time and amplitude resolution of perturbations in laser driven targets. Information of importance for research into the possibility of generating energy by inertially confined fusion has been obtained using a saturated 15.4 nm neon-like Yttrium laser [1,2,3]. More recently further work has been carried out with a neon-like Ge laser also operating at saturation with prepulse drive on the J=0-1 transition at 19.6 nm. This has enabled new avenues to be explored including the effect on the laser driven targets of single mode perturbations in the drive intensity and the transient behavior of thermal smoothing of the perturbations as illustrated by figures 1 and 2. The change in XUV opacity of the dense shock compressed target material has also been studied and is of basic science interest as it gives the first direct measurement of the scaling with density of inverse Bremsstrahlung absorption in a strongly degenerate plasma [4].
High Energy Photon Generation in Colliding Laser Pulses
Authors: Hartemann F.V. , Troha A.L. , Van Meter J.R. , Luhmann N.C. , Kerman A.K.
Published: February 2023

The acceleration of charged leptons to TeV energies is a problem of considerable importance. At these energies, electroweak spontaneous symmetry breaking and the Higgs mechanism are expected to play a dominant role in the interaction physics. Alternatively, short wavelength photons can also be used to probe this energy range, as exemplified by the γ-γ collider project [1].
Nonperturbative time-dependent theory of two-electron atoms in strong fields
Authors: Zhang Jian , Lambropoulos P.
Published: February 2023

We have developed an elaborate theoretical and computational approach for the study of strong field phenomena in two-electron atoms taking into account the electron-electron correlation in the dynamics of the process. The work grew in three stages. In the first stage, we developed the essentials of the approach which consists of a discretized L2-basis of atomic states constructed in terms of B-splines. These are completely correlated two-electron states in terms of which we expand the time-dependent wavefunction satisfying the Schrödinger equation which includes the interaction with the time-dependent laser field represented by a realistic pulse shape. Recently published results[1, 2] include ATI and photoelectron angular distributions in He which showed very small correlation effects as evaluated through a comparison with frozen core or single-active-electron calculations which are conveniently performed using the same technique.
Molecular Hydrogen in an Intense Light Field
Authors: Ludwig J. , Rottke H. , Sandner W.
Published: February 2023

The dissociation and ionization mechanisms of molecules and molecular ions in a high intensity non-perturbative optical radiation field has attracted much interest experimentally as well as theoretically ([1,2] and refs, cited there). Especially investigations on molecular hydrogen have revealed many new molecule specific high field phenomena originating in the coupled electronic and nuclear degrees of freedom. Zaviyev et al. and Yang et al. found mechanisms like bond-softening dissociation, above threshold dissociation, or multiphoton dissociation to be active in the hydrogen molecular ion [3,4,5]. Also an indication of light-induced vibrational structure in H2+ and D2+ was detected [6]. At the high intensities reached in a focused laser beam finally the molecular ion may become ionized resulting in Coulomb explosion of the remaining bare nuclei. Hints pointing to this mechanism to be active have been found in H+ and D+ kinetic energy distributions [2,6].
Non-Sequential Double Ionization of Nitrogen
Authors: Gibson G. N. , Li M. , Guo C. , Neira J.
Published: February 2023

Although the non-sequential double ionization (NSDI) of atoms has been well documented experimentally, there is still no consensus as to the physical mechanism.1 However, in an atom the only information easily obtained about the ionization process comes from ion yields versus laser intensity. For this reason, we have begun to study the multiphoton ionization of nitrogen in order to learn more about the double ionization process as there are more final state products to analyze. Specifically, if we consider the rescattering model2 for NSDI the electron ionized from N2 → N2+ would return to and further ionize the molecule creating N22+. However, the molecular double ion can then remain as N22+, dissociate into N+ + N++ K.E., or N22+ → N + N2++ K.E. or be further ionized to N23+ and again dissociate. By analyzing the ion yields for N2+, N22+, N+, and N2+ and the kinetic energies of the N+ and N2+ ion fragments we have observed the following: 1) NSDI does occur in nitrogen with approximately the same rate as in argon. 2) NSDI does not lead to the fragmentation of N22+ into any dissociation channel. From these observations, we conclude that the NSDI process in N2 always leaves the N22+ molecular ion in the metastable ground state. Furthermore, it would seem to be unlikely that the rescattering model for NSDI would lead to such final state specificity.
Generation of intense tunable 20fs pulses near 400nm using a gas-filled hollow waveguide
Authors: Korn G. , Nibbering E.T.J , Dühr O.
Published: February 2023

In this paper we describe the development and characterization of an intense continously tunable 20fs source in the region between 370nm and 420nm using high-power frequency doubled pulses from a newly developed short pulse 32fs 1kHz Ti:sapphire laser system. For the first time we demonstrate the feasibility of the generation of 20fs pulses with energies up to 20μJ in this spectral region. These pulse energies are orders of magnitude higher than achieved with previously reported approaches in the same wavelength range.
Generation of 30 TW femtosecond pulses at 10 Hz in a Ti:Sapphire laser chain
Authors: Antonetti A. , Blasco F. , Chambaret J.P. , Chériaux G. , Darpentigny G. , Hamoniaux G. , Le Blanc C. , Rousseau P. , Salin F.
Published: February 2023

The technique of chirped pulse amplification has sucessfully been applied to the amplification of sub-50fs pulses from Ti:sapphire oscillators and energies approaching 125 mJ have been achieved [1,2]. Although these pulses have very high peak power they are useful to solid-state target experiment only if they are free of any prepulse or wings below an intensity of 1011 W/cm2. We describe here a Ti:sapphire amplifier producing 30 TW pulses at 10 Hz which has been designed to produce pedestal free pulses. To reduce any prepulse, we designed the amplifier with broad transmission bandwidth, minimum material path length, high gain, and an aberration free system for stretching and recompressing the pulses [3].
Saturated Table-top Soft X-Ray Lasers by Discharge Excitation
Authors: Rocca J.J. , Tomasel F.G. , Chilla J.L.A. , Marconi M.C. , Shlyaptsev V.N. , Moreno C.H. , Benware B.R. , Gonzalez J.J.
Published: February 2023

The development of practical "table-top" sources of soft x-ray laser radiation will have a very important impact in many disciplines of science and technology. In the decade that followed the first successful soft x-ray amplification experiments [1,2], large soft x-ray amplification and significant laser output energy could only be obtained using large optical lasers as the energy source. Much progress was accomplished using as pump the same type of lasers utilized in fusion research. However, the widespread use of these sources is limited by their very large size, high cost and low accessibility. These limitations motivates the development of compact soft x-ray laser sources that can impact applications.
Generation of Intense X-Ray Laser Radiation at 8 nm in Ni-like Nd Ions
Authors: Daido H. , Kato Y. , Imani T. , Sezaki S. , Hirose S. , Yoon G. Y. , Jitsuno T. , Takagi Y. , Mima K. , Wang S. , Lin Z. , Gu Y. , Huang G. , Tang H. , Ximing D. , Zhang G. , Murai K. , Takenaka H.
Published: February 2023

Lasing in various Ni-like ions at the wavelengths below 10 nm has been demonstrated [1,2]. Achieving saturated amplification with the Ni-like ions is considered to be difficult compared with the Ne-like ions at longer wavelengths, since the plasma parameter space for amplification is narrower with the Ni-like ions [3]. In this paper we report generation of very intense x-ray laser radiation at 8 nm in Ni-like Nd ions by amplification using double curved targets. This result shows that it will be possible to achieve saturated amplification in Ni-like ions by properly optimizing the irradiation conditions and target configurations.
Synchrotron Radiation and Applications
Authors: Nenner Irène
Published: February 2023

The use of synchrotron radiation has reached a quite mature stage all over the world with dedicated electron storage rings equipped with a large number of beam lines to accommodate an even larger number of simultaneous experiments. The spectrum of the light which depends upon the energy of the accelerated particles covers continuously the electromagnetic spectrum from the infra-red to the ultra-violet up to the soft X-ray and hard X-ray range. The main characteristics are the high flux or mean power, the high brillance, the small divergence, an access to linear and circular polarization, the high spatial and temporal stability and a usable time structure. The interest and the complementarity of these sources with respect to conventional laboratory sources (X-ray tubes, discharge lamps and lasers) is now recognized and explains the growing demand in fundamental and finalized research.
Time-resolved x-ray diffraction from laser excited crystals
Authors: Larsson J. , Judd E. , Schuck P. J. , Falcone R. W. , Heimann P. A. , Padmore H. A. , Chang Z. , Kapteyn H. C. , Murnane M. M. , Lee R. W. , Machacek A. , Wark J. S.
Published: February 2023

We have constructed an ultra-fast time-dependant x-ray diffraction experiment in order to probe laser-induced phase transitions in solids. Such studies have previously been performed using laser probes in the infra-red, visible or ultraviolet spectral range. However, in order to directly probe structures in solids, it is necessary to use x-ray radiation. A laser system producing pulses with a duration of 100 fs has been set-up adjacent to a bending magnet at the Advanced Light Source (ALS). In addition an averaging streak camera with a temporal jitter smaller than 1.5 ps has been incorporated [1]. This diagnostic will permit us to study lattice disordering in materials such as Si. Single-shot measurements were also made using a Kentech streak camera.
The optimisation of soft X-ray laser output
Authors: Tallents G J , Behjat A , Demir A , Lin J Y , Smith R , Lewis C L S , MacPhee A , McCabe S P , Warwick P J , Neely D , Wolfrum E , Zhang J , Pert G J , Nickles P V , Kalashnikov M , Schnürer M
Published: February 2023

The efficiency of producing soft X-ray laser output from nanosecond duration optical pumping pulses has been found to be low (≈ 10-6)). This means that moderately large optical pumping lasers are required (typically producing 100 - 1000 joules in nanosecond pulses) and that because of the rapid scaling of efficiency with X-ray laser wavelength, the X-ray wavelengths able to be pumped with such medium-sized laser facilites are limited to typically >15 nm.
Tunneling ionization of molecules
Authors: Zon B.A.
Published: February 2023

The Ammosov–Delone–Krainov theory (ADK, [1]) is a wide-spread theory for describing the tunneling ionization of atoms in high light field. It is an important detail of this theory that the ionization probability is determined not only by the exponential factor, but also by the pre-exponential factor which depends upon the electron orbital momentum and magnetic quantum number.
Time-dependent Schrödinger equation for the interaction between a laser pulse and a one-dimensional metal
Authors: Martin P. , Petite G.
Published: February 2023

As well known, solving the time-dependent Schrödinger equation allows an accurate non pertubative description for the interaction between an intense optical field and an electron in a potential [1].
Determination of the Duration of UV Femtosecond Pulses
Authors: Ripoche J.-F. , Prade B. S. , Franco M. A. , Grillon G. , Lange R. , Mysyrowicz A.
Published: February 2023

The determination of the duration of visible or near-infrared optical pulses with subpicosecond duration has become a routine operation in ultrafast time-resolved spectroscopy. Several experimental methods have been demonstrated, which all rely on the same principle, transforming a time measurement requiring an ultrafast detector into a length measurement using a slow detector [1]. By far the most commonly used technique is the measurement of the sum frequency radiation which yields the autocorrelation of the pulse from which the pulse duration is extracted, assuming the pulse timeshape known. Recently, more sophisticated methods have been developed to obtain more precise knowledge of the pulse characteristics, such as its phase and amplitude [2-3]. However, to extend such measurements to the ultraviolet (UV) domain is a nontrivial task [4-5], for instance because of phase-matching or group velocity dispersion issues.
Increased Coherence Length in High Order Harmonic Generation by a Self-Guided Beam
Authors: Lange H.R. , Bouhal A. , Ripoche J.-F , Mysyrowicz A. , Breger P. , Agostini P.
Published: February 2023

High-order harmonics as a potential source of coherent XUV have resulted in extensive studies of this effect. One of the limitations to the efficiency of the generation process is the phase shift occurring at the focus of a gaussian beam (Goyd factor) [1]. This can be minimized by using long focal length and setting the atomic jet either before or after the focus. Self-guided beams are an attractive alternative to focused beams since they can, in principle, be made intense enough while their phase front remains flat in the high intensity region. This is because the curvatures of the wavefront due to diffraction and the Kerr effect compensate each other.
Spatial Coherence Measurement of High Order Harmonic Radiation
Authors: Ditmire T. , Gumbrell E. T. , Smith R. A. , Tisch J. W. G. , Meyerhofer D. D. , Hutchinson M. H. R.
Published: February 2023

Though a vast number of studies have been conducted on the various properties of intense field high order harmonic radiation, there have been no studies of the actual spatial coherence of optical harmonics at short wavelengths (< 1000 Å). Measurements of harmonic far field profiles have suggested that the harmonics exhibited high coherence [1,2,3], but harmonic profile measurements alone are inadequate in determining the spatial coherence of the harmonic beam [4], To address this aspect of the harmonic generation, we have conducted a series of two-slit interference measurements on harmonics in the 270 Å to 480 Å range to determine unambiguously their spatial coherence properties.
Conical Emission of a Femtosecond Pulse Undergoing Self-focusing and Ionization in Air
Authors: Kosareva O.G. , Brodeur A. , Kandidov V.P. , Chin S.L.
Published: February 2023

Recently, the phenomenon of intense femtosecond light pulse filamentation over distances of several tens of meters was observed [1,2]. The study of long-interaction-length intense laser pulses has interesting applications including laser-induced lightning, laser-pumped x-ray sources, and laser-plasma based accelerators.
A Three Dimensional Ponderomotive Trap for High Energy Electrons
Authors: Chaloupka J.L. , Kessler T.J. , Meyerhofer D. D.
Published: February 2023

Electrons injected into a high intensity laser focus by tunneling ionization quickly escape due to the strong ponderomotive force. This limits the probability of observing harmonic radiation from free electrons oscillating in the field1 and other nonlinear effects. Two dimension(radial) optical confining schemes have been proposed to increase the life-time of the electron in the intense field.2,3 These do not confine the electron in the direction of the laser propagation which limits their effectiveness. In intense fields the electrons have significant momentum in this direction.4 To our knowledge, neither of these schemes have been demonstrated.
Self-Guiding Without Focusing Nonlinearity: Leaking Mode Self-Effect due to Field-Induced Saturable Ionization
Authors: Sergeev A.M. , Lontano M. , Kim A.V.
Published: February 2023

Creation of elongated plasma structures for guiding of powerful ultra-short laser pulses is a challenging scientific problem and an important application in the area of superstrong field interaction with matter. Self-channeling regimes recently observed in experiments1-4 have been attributed to the focusing nature of relativistic and Kerr nonlinearities that cause an increase of the refractive index and deviation of light rays toward stronger field regions. In the case of gas ionization at the axis of a Kerr-effect induced waveguide3-5 the influence of focusing nonlinearity should be especially strong since it is not only to prevent the divergence of rays due to linear diffraction but also to balance refraction of radiation from the axis, that is caused by emerging plasma. Experimentally observed extra-long waveguides produced by few mJ, 100 fs laser pulses at ionization of atmospheric air3,4 have been interpreted as plasma structures having a core where the ionization nonlinearity prevails and an outer cladding where the dominating Kerr nonlinearity generates opposite-in-sign positive variations of the refractive index and hence keeps the radiation from divergence.