Intense Pulses Research Articles

Laser-accelerated MeV-scale collimated electron bunch from a near-critical plasma of a liquid jet target

Generation of a collimated electron bunch with energy of a few MeV is demonstrated experimentally during propagation of 1 TW 10 Hz femtosecond laser radiation through a near-critical plasma formed from a micrometer-scale liquid jet (ethanol) target by ablation and boring with an intense nanosecond pulse. Hydrodynamic and particle-in-cell simulations reveal the evolution of the plasma cloud and help to identify the acceleration mechanism, which is related to self-modulated laser Wakefield acceleration during nonlinear propagation of laser radiation through plasma. The measured bunch divergence is at the level of 0.04 rad with high shot-to-shot stability. The total charge of the particles with energy above 1.6 MeV was estimated at ∼15 pC. The simplicity and robustness of the target design allows for enhanced pulse repetition rate with suppressed debris formation.

Coherent modulation of intense XUV pulses by ground-state coupling

We present and validate a method to modify the interaction between laser fields and an atomic three-level system based on the control of the ground state, which is interpreted with a direct analytical formula. Coherent modulation of intense extreme Ultraviolet (XUV) pulses is achieved by using near-infrared (NIR) lasers as control pulses interacting with the atomic systems, i.e. quantum transition paths are manipulated in light-matter interactions caused by the laser. We analyze the feasibility of realizing the phase reversal of the dipole response in the three-level system by controlling the interaction between the ground state and another excited state. The discussion of the modulation of intense XUV pulses complements recent studies relying on perturbative excitation. These observations provide new insights for achieving pulse shaping of the XUV frequency range by using the NIR pulse as a control pulse.

ETV6::RUNX1 Acute Lymphoblastic Leukemia: how much therapy is needed for cure?

Recent trials show 5-year survival rates >95% for ETV6::RUNX1 Acute Lymphoblastic Leukemia (ALL). Since treatment has many side effects, an overview of cumulative drug doses and intensities between eight international trials is presented to characterize therapy needed for cure. A meta-analysis was performed as a comprehensive summary of survival outcomes at 5 and 10 years. For drug dose comparison in non-high risk trial arms, risk group distribution was applied to split the trials into two groups: trial group A with ~70% (range: 63.5–75%) of patients in low risk (LR) (CCLSG ALL2004, CoALL 07-03, NOPHO ALL2008, UKALL2003) and trial group B with ~45% (range: 38.7–52.7%) in LR (AIEOP-BFM ALL 2000, ALL-IC BFM ALL 2002, DCOG ALL10, JACLS ALL-02). Meta-analysis did not show evidence of heterogeneity between studies in trial group A LR and medium risk (MR) despite differences in treatment intensity. Statistical heterogeneity was present in trial group B LR and MR. Trials using higher cumulative dose and intensity of asparaginase and pulses of glucocorticoids and vincristine showed better 5-year event-free survival but similar overall survival. Based on similar outcomes between trials despite differences in therapy intensity, future trials should investigate, to what extent de-escalation is feasible for ETV6::RUNX1 ALL.

Clarify the contribution of shallow and deep interfacial traps to the transistor-type optoelectronic synaptic device

Recently, transistor-type optoelectronic synaptic device has garnered widespread attention due to its high potential for realizing artificial visual systems and neuromorphic computing. However, some basic mechanisms, such as the contribution of shallow and deep traps on the synaptic behavior, are still not fully understood. In this work, a channel-only transistor-type optoelectronic synaptic device has been employed as platform to clarify the contribution of shallow and deep traps to the synaptic response. We firstly demonstrated that the channel-only transistor-type synaptic device can successfully mimic almost all synaptic behavior, such as excitatory postsynaptic current spike (ΔEPSC), paired-pulse facilitation (PPF), etc. And then, two individual double-exponential models have been employed to fit the generation and decay part of ΔEPSC response to distinguish the role of shallow and deep traps on the synaptic behavior. The results suggest that the shallow trap gives rise to the fast response in both generation and decay component, and the deep trap contributes to the slow component in both generation and decay part. In addition, the number of deep traps is critical to determine the metastable current in the decay part because of the photogating effect. This explanation has been further confirmed by increasing the number of electrons that can be captured by increasing the light pulse intensity, and tuning the number of trap sites by storing the synaptic device in ambient environment or functionalizing the SiO2 surface with SAM agent containing strong electron withdrawing end group. Thus, this work not only clarify the contribution of shallow and deep traps, but also provide several strategies to tune the synaptic behavior.

Two-dimensional electro-optical multiphoton microscopy.

The development of genetically encoded fluorescent indicators of neural activity with millisecond dynamics has generated demand for ever faster two-photon (2P) imaging systems, but acoustic and mechanical beam scanning technologies are approaching fundamental limits. We demonstrate that potassium tantalate niobate (KTN) electro-optical deflectors (EODs), which are not subject to the same fundamental limits, are capable of ultrafast two-dimensional (2D) 2P imaging in vivo. To determine if KTN-EODs are suitable for 2P imaging, compatible with 2D scanning, and capable of ultrafast in vivo imaging of genetically encoded indicators with millisecond dynamics. The performance of a commercially available KTN-EOD was characterized across a range of drive frequencies and laser parameters relevant to in vivo 2P microscopy. A second KTN-EOD was incorporated into a dual-axis scan module, and the system was validated by imaging signals in vivo from ASAP3, a genetically encoded voltage indicator. Optimal KTN-EOD deflection of laser light with a central wavelength of 960nm was obtained up to the highest average powers and pulse intensities tested (power: 350mW; pulse duration: 118fs). Up to 32 resolvable spots per line at a 560kHz line scan rate could be obtained with single-axis deflection. The complete dual-axis EO 2P microscope was capable of imaging a by field-of-view at over 10kHz frame rate with lateral resolution. We demonstrate in vivo imaging of neurons expressing ASAP3 with high temporal resolution. We demonstrate the suitability of KTN-EODs for ultrafast 2P cellular imaging in vivo, providing a foundation for future high-performance microscopes to incorporate emerging advances in KTN-based scanning technology.

Second-harmonic generation of ultrashort pulses in refractive index linearly modulating quantum dot structure

While other works use segments of nonlinear crystal to compensate for walk-off, this work utilizes a quantum dot (QD) nanostructure for such compensation. Such nanocrystal structures allow two benefits: the high nonlinear susceptibility in these nanocrystals and the high surface density of QDs in the structure. Good results are obtained for pre-chirping and modulation parameters. The results are computed at 10 and 100 kV/cm applied electric fields. Compared to ordinary nonlinear crystals, the pulse width, intensity, and efficiency of the second harmonic (SH) pulse are all higher in QD nanocrystals, even with a low electric field applied. Higher applied fields give higher results.

Change in Transmittance of Indium-Tin-Oxide-Coated Silicon Waveguides Exposed to Intense Light Pulses

Change in Transmittance of Indium-Tin-Oxide-Coated Silicon Waveguides Exposed to Intense Light Pulses

Pulse Intensity Coding Phase-Sensitive OTDR With Mismatched Filtering

Pulse Intensity Coding Phase-Sensitive OTDR With Mismatched Filtering

Режимы синхронизации мод в лампе бегущей волны с цепью обратной связи

The generation of sequences of short correlated pulses in a traveling wave tube (TWT) with a feedback circuit in mode locking regime are considered. It is shown that in a system with parameters corresponding to an experimentally implemented W-band TWT with a linear feedback circuit, it is possible to generate pulses whose peak intensity is several times the average power level. In turn, a significant increase in the peak pulse intensity can be achieved by adding a saturable absorber to the feedback circuit.

Objective Evaluation of Stellate Ganglion Block Effects Using Ultrasound Wave Intensity Technology: A Study on Hemodynamics.

Emerging evidence suggests that although Horner's syndrome manifests observable facial changes, it may not comprehensively evaluate the hemodynamic alterations associated with stellate ganglion block (SGB). This study endeavors to systematically evaluate the influence of SGB on the elasticity and flow velocity of the common carotid artery (CCA) and brachial artery utilizing ultrasound wave intensity analysis (usWIA). Particularly, it focuses on patients necessitating monitoring for its effects on specific organs or regions. Totally, we selected 33 patients, where only 31 patients (comprising 15 males and 16 females) were included between September 2020 to January 2022 after screening patients who require SGB treatment for painful disorders. The side on which the SGB was administered depended on the patient's painful side, 13 cases underwent left stellate ganglion block (LSGB), and 18 cases underwent right stellate ganglion block (RSGB). Wave intensity (WI) data were collected by usWIA on the CCA and brachial artery before the administration of SGB and after the manifestation of Horner's syndrome. We then compared the changes in these data pre- and post-SGB using SPSS 26.0. The results showed an increase in arterial compliance (AC) of the CCA and brachial artery on the blocked side after SGB (P < 0.05). In contrast, pressure-strain elastic modulus (EP) and arterial stiffness pulse wave velocity (PWVβ) decreased (for all P < 0.05). Furthermore, the minimum velocity (Vmin) of the CCA exhibited a significant increase (P < 0.01), while wave intensity pulse wave velocity (PWVwi) was significantly reduced (P < 0.01). In contrast, on the contralateral side of the CCA, EP and PWVβ increased after SGB (for all P < 0.05), while AC decreased (P < 0.05). SGB has been observed to enhance the elasticity and blood flow velocity of arteries within its innervated areas. In clinical practice, usWIA can serve as an objective measurement tool for assessing the impact of SGB on arterial elasticity and flow velocity in specific organs or regions. Furthermore, unilateral SGB has been noted to diminish the arterial elasticity of the CCA on the contralateral side.

Ionizing terahertz waves with 260 MV/cm from scalable optical rectification.

Terahertz (THz) waves, known as non-ionizing radiation owing to their low photon energies, can actually ionize atoms and molecules when a sufficiently large number of THz photons are concentrated in time and space. Here, we demonstrate the generation of ionizing, multicycle, 15-THz waves emitted from large-area lithium niobate crystals via phase-matched optical rectification of 150-terawatt laser pulses. A complete characterization of the generated THz waves in energy, pulse duration, and focal spot size shows that the field strength can reach up to 260 megavolts per centimeter. In particular, a single-shot THz interferometer is employed to measure the THz pulse duration and spectrum with complementary numerical simulations. Such intense THz pulses are irradiated onto various solid targets to demonstrate THz-induced tunneling ionization and plasma formation. This study also discusses the potential of nonperturbative THz-driven ionization in gases, which will open up new opportunities, including nonlinear and relativistic THz physics in plasma.

Investigation on gaseous molecular alignment echoes induced by the intense phase-tunable terahertz pulses

Investigation on gaseous molecular alignment echoes induced by the intense phase-tunable terahertz pulses

#2644 Clinical impact of proteinuria and hematuria remission criteria in IgA nephropathy patients defined by the Japanese Society of Nephrology

Abstract Background and Aims IgA nephropathy (IgAN) is one of the most common glomerulonephritis worldwide, especially in the Pacific Rim and Mediterranean countries. Hematuria is almost inevitable clinical findings and massive proteinuria is well established risk factor in IgAN. However, a few studies reported hematuria and proteinuria remission in IgAN, and their definition varies in clinical studies. The Japanese Society of Nephrology (JSN) defined new criteria for hematuria and proteinuria remission and relapse for IgAN patients. The objective of the present study was to analyze the utility of JSN criteria to predict renal prognosis among IgAN patients after immunosuppressive treatment. Method One hundred IgAN patients were recruited between 2003 and 2014 at Nagoya University Hospital and followed up until December 2017. According to JSN criteria, hematuria remission (HR) and proteinuria remission (PR) are defined as &amp;lt; 5 RBC/HPF, and &amp;lt; 0.3 g/g Cr, in three consecutive urine exams over six months of observation, respectively. Clinical remission (CR) is defined as both HR and PR in 3 consecutive urinalysis over six months. HR, PR and CR were analysed with 30% eGFR decline as a renal outcome. Results Baseline proteinuria, serum creatinine, and eGFR were 1.3g/day, 0.8 mg/dL, and 80 mL/min/1.73 m2. The mean age was 34.7 ± 12.5 years old, and 61% of the study population was female. Seventy-two percent of patients received intensive methylprednisolone pulse therapy (mPSL), and the incidence of HR, PR and CR were 76, 50 and 46%, 50%, respectively. Kaplan-Meier curves analyses showed a significant difference between HR and non-HR, PR and non-PR, and CR and non-CR groups (Fig.). In univariate analyses, hypertension, eGFR, HR, PR, CR, and T-score in the Oxford classification of IgAN were significantly associated with renal outcome. In multivariate Model-A, HR, and PR were significant factors for renal outcome after adjusting with sex, hypertension, eGFR and T-score. While in multivariate model-B, CR was also significantly associated with renal outcome after adjustment (Table). However, 36% and 46% of patients demonstrated hematuria and proteinuria relapses after remission. Conclusion JSN novel criteria for HR and PR predict renal outcomes in IgAN patients. Further studies are required to verify their clinical utility of JSN criteria in a larger sample size with different ethnicities.

Machinability and pulse characteristics of Ti-16Al-14Nb (α/β) alloy in wire-electric discharge machining process: A surface integrity study

The goal of the present work is to produce the efficient cutting of Ti-16Al-14Nb (α/β) alloy through wire-electric discharge machining and contemplate the terminologies such as machining ability, surface integrity and material removing capability. For this, the experimentation has been designed by considering three process parameters, pulse-on time ( Ton), pulse-off time ( Toff) and peak current ( Ip) at three significant levels (low, high, intermediate) in L27 order designed from design of experiments. The effect of these process variables on pulse characteristics, surface roughness ( Ra), kerfwidth ( Kw) and material removal rate ( MRR) is analyzed and mathematically modeled with analysis of variance. The results state that the highest MRR (0.521, 0.51, 0.506 mm3/sec) and low surface roughness (8.91, 8.89, 8.68 µm) values are observed at the highest level (110 µs, 15 µs, 8 A). If the pulse duration is kept at low ( Ton = 40µs, Toff = 3µs), the increase in peak current from 3 A to 8 A leads to a 64.54% increase in MRR and a 52.9% increase in Ra values. ANOVA results stated that Ton has contributed 20.4%, 35.8% and 19.3%, and Ip has contributed 43.1%, 30.5% and 46.6% influence on MRR, Kw and Ra respectively. The voltage–current characteristics studies confirmed that the strong intense pulses at a higher peak current (8 A) resulted in the increased MRR (0.521 mm3/sec) and Ra (8.43 µm) leading to the formation of swages and ridges. The surface integrity analysis derived from Abbott–Firestone curve agreed that the lowest level has shown better skewness ( Rsk = −0.274) and at highest level showed a larger deviation in skewness ( Rsk = +2.672) signifies that higher asymmetry (poor) of the surface.

All-optical control of skyrmion configuration in CrI monolayer.

The potential for manipulating characteristics of skyrmions in a CrI monolayer using circularly polarised light is explored. The effective skyrmion-light interaction is mediated by bright excitons whose magnetization is selectively influenced by the polarization of photons. The light-induced skyrmion dynamics is illustrated by the dependencies of the skyrmion size and the skyrmion lifetime on the intensity and polarization of the incident light pulse. Two-dimensional magnets hosting excitons thus represent a promising platform for the control of topological magnetic structures by light.

High-precision spatiotemporal three-dimensional ultrashort pulse synchronization with optical Kerr effect

In studying the interaction of multiple ultrashort pulses with matter, high requirements are put forward for spatiotemporal synchronization accuracy. Limited by the response time and bandwidth of existing devices, the synchronization of multiple ultrashort pulses still faces significant difficulties. By observing the transient phenomena of the optical Kerr effect, high-precision, three-dimensional (x, y, t) synchronization of ultrashort pulses at different angles was achieved. In the optical Kerr effect, the polarization state of the signal pulse changes only when it coincides with the pump pulse, at which point the signal pulse passes through the analyzer. The changes in the intensity and phase of the signal pulse is positively correlated with the degree of spatiotemporal coincidence. In this study, 10-ps pulses were used in the experiments. By observing the intensity and phase distribution of the signal pulses, a time synchronization accuracy between two pulses of less than 1 ps and spatial synchronization accuracy of ±125 µm and ±3 µm in the x and y directions, respectively, were achieved. Moreover, the synchronization of two pulses at an angle of 90 ° was measured, further proving that the method can achieve the spatiotemporal synchronization of pulses with large angles. Therefore, this method has important application prospects in the study of multi-beam interactions with matter and other ultrafast physical phenomena.

Generation of soliton molecules in a 1.5-μm ultrafast fiber laser based on Zinc 2,5-dihydroxyterephthalate saturable absorber

Two-dimensional (2D) Zinc 2,5-dihydroxyterephthalate (Zn-MOF-74) is a kind of metal–organic framework (MOF), which has been intensively studied in gas adsorption, gas storage, and catalysis. However, the potential applications of Zn-MOF-74 in the fields of optics, especially in the areas of nonlinear optical response and ultrafast optics need further exploration. Here, the nonlinear optical properties of Zn-MOF-74 are systematically investigated. In this work, we demonstrate that it gradually becomes saturated with the increase of the intensity of the incident pulse, which makes Zn-MOF-74 an effective saturable absorber in a mode-locked Er-doped fiber laser for ultrashort pulse generation. Our experiments yield stable single solitons as well as soliton molecules with tunable characteristics. When the pump power is 126 mW, conventional solitons with an output power of 2.35 mW and a pulse width of 0.93 ps are obtained. The generated pulses characterize a central wavelength of 1554.84 nm and a 3-dB bandwidth of 3.07 nm. By adjusting the pump power and polarization appropriately, the center wavelength of the soliton molecules is tunable from 1532.76 nm to 1554.24 nm. The experimental observations further proves that Zn-MOF-74 has great potential in ultrafast optics.

Time-resolved THz Stark spectroscopy of molecules in solution

For decades, it was considered all but impossible to perform Stark spectroscopy on molecules in a liquid solution, because their concomitant orientation to the applied electric field results in overwhelming background signals. A way out was to immobilize the solute molecules by freezing the solvent. While mitigating solute orientation, freezing removes the possibility to study molecules in liquid environments at ambient conditions. Here we demonstrate time-resolved THz Stark spectroscopy, utilizing intense single-cycle terahertz pulses as electric field source. At THz frequencies, solute molecules have no time to orient their dipole moments. Hence, dynamic Stark spectroscopy on the time scales of molecular vibrations or rotations in both non-polar and polar solvents at arbitrary temperatures is now possible. We verify THz Stark spectroscopy for two judiciously selected molecular systems and compare the results to conventional Stark spectroscopy and first principle calculations.

Scaling relations in laser-induced vaporization of thin free-flying liquid metal sheets

We experimentally study the vaporization of free-flying liquid tin sheets when exposed to a 100-ns laser pulse with an intensity between 0.2×107 and 4×107 W/cm2, a case inspired by current developments around “advanced target shaping” in industrial laser-produced plasma sources for extreme ultraviolet (EUV) nanolithography machines. Our findings reveal a gradual vaporization and a linear relationship between the average vaporization rate and laser pulse intensity (with a prefactor of 1.0(3)×10−7ms−1/Wcm−2), for various targets ranging from 20nmto200nm in thickness. We introduce a numerical one-dimensional heating and vaporization model based on Hertz-Knudsen evaporation and find excellent agreement between simulations and experimental data. We furthermore demonstrate that the amount of vaporization of liquid tin targets in the investigated laser intensity range is governed solely by the deposited fluence, and collapse all data onto a single nondimensional curve, enabling the accurate prediction of vaporization dynamics in applications in future development of EUV sources. Published by the American Physical Society 2024

Ultrabright attosecond gamma ray from irradiating solid foil with tailored vortex laser pulse

Intense attosecond light sources are required for investigating ultrafast electron dynamics, such as that in molecules and atoms, etc. However, so far the achievable photon energy remains at the keV level, thereby limiting their range of applications. For instance, probing intranuclear dynamics requires photon energies in the gamma-ray regime. We propose here a scheme for generating intense attosecond gamma-ray pulses by irradiating a thin solid-density foil with intense vortex laser. In the interaction, the laser driven-foil electrons are differentially accelerated within a quarter-wave field and become highly bunched. Three-dimensional particle-in-cell simulations show that they can efficiently (with ∼30% energy conversion efficiency) radiate ultrashort ( ∼400 as), high-flux ( >1010 photons per pulse), and ultrabrilliant (up to 1027 photons s−1 mm−2 mrad−2 per 0.1% BW at 1 MeV photon energy) gamma rays. With an x-ray driving laser, the scheme can even produce isolated bright sub-attosecond gamma-ray pulses that are useful for time-resolved nuclear spectroscopy and many other areas.