Journal articles: 'Pulsed mode'

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Flood, C. J., G. Giuliani, and H. M. van Driel. "Pulsed electro-optic modulation for efficient, active continuous-wave laser mode-locking." Canadian Journal of Physics 71, no. 1-2 (1993): 1–4. http://dx.doi.org/10.1139/p93-001.

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We demonstrated efficient active mode-locking of a Nd:YAG laser using broad bandwidth, pulsed electro-optic modulation. A 10 GHz, LiTaO3 traveling wave phase modulator, driven by 300 ps FWHM electrical pulses with less than 1 mW of drive power, was used to generate detector-limited, mode-locked laser pulses of less than 50 ps duration at 76 MHz. Shorter modulator drive pulses are possible and near bandwidth-limited mode-locked pulses should be attainable. The use of pulsed modulation rather than conventional sinusoidal modulation permits both pulse width and pulse build-up time reductions and generally makes active mode-locking competitive with passive mode-locking for relatively low-gain and narrow-bandwidth lasers.

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Kazachkov, E. L., O. V. Safronov, E. A. Kazachkova, E. N. Ignatieva, I. V. Safronova, and L. B. Tarasova. "Morphological substantiation of laser exposure parameters and modes for surgical treatment of intrauterine pathology." Ural Medical Journal 22, no. 2 (2023): 24–33. http://dx.doi.org/10.52420/2071-5943-2023-22-2-24-33.

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Introduction No data on experimentally substantiated parameters and modes of diode laser radiation allowing a minimally traumatic surgical treatment of intrauterine pathology have been found in the literature.The aim of the investigation was to substantiate experimentally the optimum parameters and modes of diode laser radiation in the treatment of intrauterine pathology based on the study of morphological changes in the endometrium.Materials and methods 48 endometrial samples were exposed to 10-40 W diode laser power in a constant mode and 15 samples - in a pulsed mode with 3 different sets of laser exposure parameters. The data were statistically processed using Microsoft Excel spreadsheets, version 16.49. The differences were considered statistically significant at р<0.05.Results Width of the ablation zone, lateral coagulation and hyperthermic exposure zone was calculated at the most optimal parameters of laser energy (20 W), achieving adequate cutting and bleeding properties of the laser. The most effective in the pulsed mode of laser operation was 30 W amplitude power of radiation, the pulse duration of 100 ms, the duration of the interval between pulses of 50 ms, the average power of 20 W.Discussion Comparative analysis of morphometric parameters in the action of laser radiation in the constant mode with a radiation power of 20 W and in the pulsed mode with an average laser power of 20 W has shown that the structural parameters have significantly lower values in the pulsed laser mode.Conclusion Optimal cutting properties of the laser are observed when constant laser irradiation with a power of 20 W is used. The best cutting and bleeding properties were demonstrated by the pulsed laser mode with an average power of 20 W, amplitude power of 30 W, pulse duration of 100 ms, and inter-pulse interval of 50 ms.

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Shemyakin, A. N., M. Yu Rachkov, N. G. Solov’ev та M. Yu Yakimov. "Radiation Power Control of the Industrial CO₂ Laser Excited by а Nonself-Sustained Glow Discharge by Changing the Frequency of Ionization Pulses". Mekhatronika, Avtomatizatsiya, Upravlenie 21, № 4 (2020): 224–31. http://dx.doi.org/10.17587/mau.21.224-231.

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The article describes radiation power control of industrial CO2 lasers of Lantan series excited by а nonself-sustained glow discharge in the automatic mode. These lasers are closed-cycle fast gas-transport lasers excited by a nonself-sustained glow discharge with ionization by periodic-pulsed capacitively coupled auxiliary discharge. In this case, ionization and conductivity are provided by periodic-pulsed capacitively coupled discharge. The energy contribution to molecular oscillations is provided by the passage of the main discharge current through the plasma with electron density given by ionization. This permits easy laser power control, provides excellent optical homogeneity and stability of an active volume together with high laser efficiency. A system of a nonself-sustained glow discharge with ionization by periodic-pulsed capacitively coupled auxiliary discharge, the stages of creation and brief characteristics of the Lantan series lasers is presented. The method of controlling the power of laser radiation by changing the frequency of the ionization pulses is determined. This control method allows operating of the laser in continuous and in pulse-periodic modes with adjustable pulse ratio and pulse duration, and also provides switching from one mode to another. In the continuous mode, the radiation power is controlled by changing the frequency of ionization pulses, which are high voltage pulses with duration of 100 ns, given with the frequency of 1-5 kHz. Pulse-periodic radiation control is performed by modulating ionization pulses that consists of pulses being delivered in batches. The frequency of the pulses in a batch determines the radiation power in a pulse. The frequency of the batches following is the frequency of the pulse mode, and the length of the batch determines the pulses duration. Based on the experimental data, the dependence of the radiation power on the ionization pulses frequency was determined. An experimental system is presented and the measuring accuracy of the laser radiation power and the frequency of ionization pulses is determined. Data acquiring and processing of experimental results were performed using the NI 6008 USB data acquisition device in the LabVIEW programs of National Instruments. To study the dependence of the laser power on Мехатроника, автоматизация, управление, Том 21, № 4, 2020 231 the frequency of the ionization pulses, a regression analysis method was applied. Studies have shown that the dependence of the laser power on the ionization pulses frequency is linear in a wide range of parameters. The equation of the direct regression is calculated. The confidence estimates of the coefficients of the direct regression and the confidence estimates of the deviation of the theoretical direct regression from the empirical one are calculated with a confidence level of 95%.

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Ge, Boyuan, Yajun Lou, Silin Guo, Yue Cai, and Xinhai Zhang. "A High-Energy, Wide-Spectrum, Spatiotemporal Mode-Locked Fiber Laser." Micromachines 15, no. 5 (2024): 644. http://dx.doi.org/10.3390/mi15050644.

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In this article, we demonstrate a high-energy, wide-spectrum, spatiotemporal mode-locked (STML) fiber laser. Unlike traditional single-mode fiber lasers, STML fiber lasers theoretically enable mode-locking with various combinations of transverse modes. The laser can deliver two different STML pulse sequences with different pulse widths, spectra and beam profiles, due to the different compositions of transverse modes in the output pulses. Moreover, we achieve a wide-spectrum pulsed output with a single-pulse energy of up to 116 nJ, by weakening the spectral filtering and utilizing self-cleaning. Strong spatial and spectral filtering are usually thought to be necessary for achieving STML. Our experiment verifies the necessity of spatial filtering for achieving STML, and we show that weakening unnecessary spectral filtering provides an effective way to increase the pulse energy and spectrum width of mode-locked fiber lasers.

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Kokovin, A. O., A. V. Kozyrev, and V. Yu Kozhevnikov. "Simulation of negative corona discharge in atmospheric air: from mode of Trichel pulses to stationary discharge." Journal of Physics: Conference Series 2064, no. 1 (2021): 012024. http://dx.doi.org/10.1088/1742-6596/2064/1/012024.

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Abstract The paper presents a 2D multi-fluid non-stationary model of a negative corona discharge in atmospheric-pressure air in the needle-to-plane diode. Discharges were simulated in gaps up to 1 cm with an applied voltage in the range of 8-100 kV. The simulation results demonstrate two stages of the discharge evolution: a pulsed-periodic stage called the Trichel pulses mode and a stationary glow discharge mode. The spatio-temporal distributions of the discharge plasma and electric field are shown in detail. Physical mechanism of Trichel pulses formation and transition to the stationary discharge are also revealed. The duration of the Trichel pulse mode gradually decreases with increasing of the applied voltage.

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Morozovych, V. V., and Yu O. Lyashenko. "Morphological structure of galvanized copper layers in inhomogeneous regimes." Cherkasy University Bulletin: Physical and Mathematical Sciences, no. 1 (2022): 64–73. http://dx.doi.org/10.31651/2076-5851-2021-64-73.

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The microstructure of copper layers obtained by electrodeposition in stationary, pulsed and stochastic modes on copper substrates was studied by means of scanning electron microscopy. It was found that the shape of the applied grains differs significantly in the case of pulsed and stationary application modes. The technology of production of electrodeposited layers in stationary, pulse and stochastic modes of copper on copper substrates is worked out in the work. The developed automated software and hardware complex was used to control the electrodeposition process. The effect of electrodeposition in different modes on the structure of copper surface layers was investigated using scanning electron microscopy. Qualitative examination of SEM images of electrodeposited surfaces showed that in the case of stochastic and stationary modes of electrodeposition, a coating with a larger grain size is formed than in the case of pulsed deposition. It should also be noted that the shape of the applied grains is significantly different in the case of pulsed and stationary application modes. In the process of electrodeposition in the stationary mode, sediment is formed in the form of conglomerates of grains of different sizes, while in the pulse mode, a uniform grain structure is formed. The shape of the grains formed in the process of electrodeposition in the stochastic mode is different in that the coating has areas with evenly distributed grains and conglomerates of grains. The average grain size in the electrodeposited layers obtained using the pulse mode increases with increasing pulse period. It was also found that the average grain size is smaller in the case of the stochastic application method than in the case of the pulsed method, for the same average current density

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Ustimchik, V., E. Motorin, and V. Filippov. "High peak/average power picosecond pulsed MOPA system with tapered large mode area double-clad Yb-doped fiber." EPJ Web of Conferences 266 (2022): 11014. http://dx.doi.org/10.1051/epjconf/202226611014.

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In this paper, a high peak/average power picosecond pulsed master‑oscillator power‑amplifier (MOPA) system utilizing tapered large mode area double-clad fiber (T-DCF) is presented. In a high average power regime, we report a pulsed MOPA laser system with average power up to 613 W at 20 MHz repetition rate with 50 ps pulse duration (613 kW of peak power and 30.6 μJ pulse energy). In high peak power regime, over 3MW of peak power pulses (at seed source bandwidth) at 1 MHz repetition rate (310 μJ pulse energy and 310 W average) was demonstrated. The outstanding properties of T-DCF for amplification of laser signals to high power/energy levels with maintaining the excellent beam quality open a new horizon for advanced laser material processing.

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Kandratsyeu, Aleh, Uladzimir Sabaleuski, Luis Redondo, and Andrei G. Pakhomov. "Four Channel 6.5 kV, 65 A, 100 ns–100 µs Generator with Advanced Control of Pulse and Burst Protocols for Biomedical and Biotechnological Applications." Applied Sciences 11, no. 24 (2021): 11782. http://dx.doi.org/10.3390/app112411782.

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Pulsed electric fields in the sub-microsecond range are being increasingly used in biomedical and biotechnology applications, where the demand for high-voltage and high-frequency pulse generators with enhanced performance and pulse flexibility is pushing the limits of pulse power solid state technology. In the scope of this article, a new pulsed generator, which includes four independent MOSFET based Marx modulators, operating individually or combined, controlled from a computer user interface, is described. The generator is capable of applying different pulse shapes, from unipolar to bipolar pulses into biological loads, in symmetric and asymmetric modes, with voltages up to 6.5 kV and currents up to 65 A, in pulse widths from 100 ns to 100 µs, including short-circuit protection, current and voltage monitoring. This new scientific tool can open new research possibility due to the flexibility it provides in pulse generation, particularly in adjusting pulse width, polarity, and amplitude from pulse-to-pulse. It also permits operating in burst mode up to 5 MHz in four independent channels, for example in the application of synchronized asymmetric bipolar pulses, which is shown together with other characteristics of the generator.

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Giner, J., V. Gimeno, G. V. Barbosa-Cánovas, and O. Martín. "Effects of Pulsed Electric Field Processing on Apple and Pear Polyphenoloxidases." Food Science and Technology International 7, no. 4 (2001): 339–45. http://dx.doi.org/10.1106/mj46-8j9u-1h11-t0ml.

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The feasibility of inhibiting polyphenoloxidase from apple and pear by pulsed electric field processing was evaluated. These treatments significantly lowered polyphenoloxidase activity of enzyme extracts from apple ( Golden deliciousvar.) and pear ( Blanquillavar.). Exponential decay pulses were generated by a laboratory scale electric pulse generator and applied in bipolar mode. Pulse duration was 0.02 ms and electric field intensities were up to 24.6 kV/cm. The temperature of samples never exceeded 15 ºC during pulsed electric field processing treatments. Polyphenoloxidase activities were reduced up to 3.15% and 38.0% initial value in apple extract at 24.6 kV/cm and pear extract at 22.3 kV/cm both for 6 ms total treatment time, respectively. Apple and pear polyphenoloxidase exposed to pulsed electric field processing diminishes their activities following first order kinetics. Rate constants ranged from 132 to 440 ms 1 for apple polyphenoloxidase, whereas for pear 1 and changed exponentially with the applied electric field intensity. Residual polyphenoloxidase activity was correlated to energy density by an exponential decay model.

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Nikitin, V. S., T. N. Ostanina, V. M. Rudoy, and N. I. Ostanin. "A Model Describing the Process of the Electrodeposition of Zinc Loose Deposits in Pulsed Current Modes." Электрохимия 59, no. 7 (2023): 391–403. http://dx.doi.org/10.31857/s0424857023070071.

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A phenomenological model describing the change in the structural characteristics of loose zinc deposits obtained in pulsed current modes is presented. Comparison of experimental data on the structural properties of deposits with the results of model calculations indicates the adequacy of the model. To describe the features of the dendritic deposit growth and to determine the duration of the homogeneous structure formation in pulsed modes, the concept of critical thickness is introduced, at which a sharp change in the loose deposit density occurs. The dependence of the zinc deposit critical thickness on the pulse duty ratio under pulsed current modes is determined. The increasing of the pulse duty ratio leads to denser deposits with rounded dendrite shapes and fewer growth points, as compared with the deposit obtained in galvanostatic mode.

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Miraval Zanon, A., F. Ambrosino, F. Coti Zelati, et al. "UV and X-ray pulse amplitude variability in the transitional millisecond pulsar PSR J1023+0038." Astronomy & Astrophysics 660 (April 2022): A63. http://dx.doi.org/10.1051/0004-6361/202243180.

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The transitional millisecond pulsar PSR J1023+0038 is the first millisecond pulsar discovered to emit UV and optical pulses. Here we present the results of the UV and X-ray phase-resolved timing analysis of observations performed with the Hubble Space Telescope, XMM-Newton, and NuSTAR satellites between 2014 and 2021. Ultraviolet pulsations are detected in the high luminosity mode and disappear during low and flaring modes, similar to what is observed in the X-ray band. In the high mode, we find variability in both the UV and X-ray pulse amplitudes. The root mean square pulsed amplitude in the UV band ranges from ~2.1% down to ~0.7%, while it oscillates in the interval 5.5–12% in the X-ray band. As also observed in the optical band, this variability is not correlated with the orbital phase. Notwithstanding the rather low statistics, we have marginal evidence that variations in the pulse amplitude do not occur simultaneously in the UV and X-ray bands. When the UV pulsed amplitude decreases below the detection threshold, no significant variation in the X-ray pulsed amplitude is observed. These oscillations in the pulse amplitude could be caused by small random variations in the mass accretion rate leading to a variation in the size of the intra-binary shock region. Finally, we find that the pulsed flux spectral distribution from the X-ray to the UV band is well fitted using a power-law relation of the form νFνpulsed∼ν0.4. This supports the hypothesis of a common physical mechanism underlying the X-ray, UV, and optical pulsed emissions in PSR J1023+0038.

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Bostanjoglo, O., F. Heinricht, and F. Wünsch. "Performance of A Laser-Pulsed Thermal Electron Gun." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (1990): 124–25. http://dx.doi.org/10.1017/s0424820100179373.

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High-speed electron microscopy strongly demands a high-brightness electron gun in order to increase the number of image forming electrons. A few years ago, a laser-pulsed high-brightness electron gun was introduced. Fig.1 shows the experimental set-up, A standard triode system was supplemented with a Nd:YAG laser, focussing optics and a modified anode, which incorporates the laser deflection mirror. The frequency doubled laser pulse (τ =5 ns, λ = 532 nm) is focused through a window onto the tip of the tungsten hairpin emitter. The laser treated area (≈ 100 μm diameter) is heated well above the melting point, which results in a strong thermal electron emission. Due to rapid heat-up and fast cool-down of the tungsten surface short electron pulses with a duration of 20 ns and a maximum current of 20 mA at 80 kV are emitted. A destruction of the tungsten wire is avoided, too. Laser energies used for the generation of electron pulses are in the range of 100 μJ. Due to these minor modification, the DC operation of the electron gun is not disabled, which allows a convenient adjustment in the DC mode and then switching into the pulsed operation mode. Fig.2 shows a typical electron pulse emitted by the gun. Shorter electron pulses up to 5 ns can be generated by a beam blanking unit.

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Li, Zerui. "Analysis of the Principles and Applications of Ultra-intensity and Ultrashort Laser." Highlights in Science, Engineering and Technology 76 (December 31, 2023): 441–49. http://dx.doi.org/10.54097/9s9fm882.

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With the development of laser technology, how to improve the output performance and peak power of lasers has become one of the hot directions of current research. This study analyzes the principles and applications of ultra-intensity and ultrashort pulse laser. It firstly outlines the development history of laser technology and the basic definition of ultra-intensity and ultrashort pulse laser. It also mentions the realization methods for generating ultra-intensity and ultrashort pulse lasers, such as mode-locked femtosecond oscillators and CPA-based femtosecond amplifiers. The paper describes the principles of CPA technique and emphasizes its importance in realizing high power ultrashort pulses. The paper discusses various applications of ultra-intensity and ultrashort pulsed laser and summarizes and discusses the major bottlenecks facing current and future ultra-intensity and ultrashort pulsed lasers and their possible solutions. The technical review in this paper aims to enhance the understanding of ultra-intensity and ultrashort pulsed laser and provide insights into the next phase of research exploration in ultra-intensity and ultrashort pulsed lasers.

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Gao, Yuan, Pan Guo, Mengyin Xu, Zhiwei Feng, and Sha Wang. "Q-switched single-longitudinal-mode Nd:YAG laser based on composite mode selection mechanism." Laser Physics Letters 22, no. 5 (2025): 055001. https://doi.org/10.1088/1612-202x/adca98.

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Abstract An electro-optical modulator (EOM) Q-switched Nd:YAG pulsed laser at 1.06 μm with single-longitudinal-mode (SLM) output is demonstrated. The enhancement of the longitudinal mode selection and the generation of SLM are provided by both the birefringence filtering technique by fine-tuning the EOM and the reflection interferometer compound cavity. The working principles of composite longitudinal mode suppression techniques are analyzed theoretically. Experimentally, we also verified that by using the composite longitudinal mode suppression techniques, the SLM operation with a high SLM ratio of up to 100% during a 1 h test is maintained without a feedback loop. The SLM laser operates at a repetition frequency of 500 Hz, producing 60 ns pulses with a pulse energy of 183.6 μJ. The result indicates that the proposed method is a simple and effective scheme for improving the stability of SLM operation.

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Gribacheva, V., and S. Shcherbakov. "THE COOLING SYSTEM OF THE PERIODIC PULSED REACTOR." PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. SERIES: NUCLEAR AND REACTOR CONSTANTS 2021, no. 2 (2021): 256–67. http://dx.doi.org/10.55176/2414-1038-2021-2-256-267.

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The paper proposes the configuration and composition equipment of the cooling system of the designed periodic pulsed reactor (PPR) of high power. The special features of the PPR are a small flow section, a large heating of the coolant in the power pulse and the impossibility of useful use of thermal energy in the periodic mode of operation. Liquid lithium is proposed as a coolant and heat is discharged through air heat exchangers (AHE). The goal was to achieve compactness and low power consumption, the ability to work with frequent stops and optimize the operation of equipment in pulse modes. For this purpose, high-temperature AHE with a small heat exchange surface and forced air cooling are used, the circulation circuit is divided into two parts - the reactor circuit and the AHE circuit with two circulation pumps and a common drain tank. The separation of the circuit allows to independently perform the operations of starting, stopping and heating the circuits in a periodic mode. The drain tank limits the composition of the equipment exposed to temperature pulses. Numerical studies of the temperature regime of the coolant in the equipment of the PDR cooling system are carried out. The calculations were performed using the TURBOFLOW code in two-dimensional terms for all the main elements of the equipment. Quasi-stationary (nominal and partial power levels) and pulse modes of operation are considered. Calculated characteristics for forced and natural air circulation are obtained. The limits of the air circulation modes under the conditions of non-freezing of the coolant are determined. The obtained values of the maximum temperatures of the coolant: in the pulsed mode is 750 °C, in the quasi-stationary mode - 490 °C with an average power of 15 MW, air flow of 150 m3/s and the size of the AHE in the plan of 5×5 m, 100 panels of 1.08×0.025×5 m.

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Chernyshova, O. V., T. B. Yelemessov, and D. V. Drobot. "Application of pulse current for dissolution of heat-resistant GS32-VI alloy." Fine Chemical Technologies 16, no. 5 (2021): 438–47. http://dx.doi.org/10.32362/2410-6593-2021-16-5-438-447.

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Objectives. To identify the regularities of electrochemical processing of the heat-resistant GS32-VI alloy in a sulfuric acid electrolyte with a concentration of 100 g/dm3 under the action of a pulsed current in a pulsed mode.Methods. Using the electrochemical technological complex EHK-1012 (developed by IP Tetran) and a non-compensatory method of measuring potential, polarization and depolarization curves with a change in pulse duration and a pause between them were recorded. The current pulses had an amplitude ranging from 0 to 3.5 A (when recording the polarization and depolarization curves), pulse durations ranging from 200 to 1200 ms, and a pause (delay) between pulses ranging from 50 to 500 ms. There were no reverse current pulses.Results. The parameters of the current program that provide the maximum values of the alloy dissolution rate and current output were determined: with a current pulse amplitude of 2 A, a current pulse duration of 500 ms, and a pause duration between pulses of 250 ms, the maximum dissolution rate of the alloy is 0.048 g/h·cm2, while the current output for nickel is 61.6% with an anode area of 10 cm2. The basic technological scheme for processing the heat-resistant GS32-VI alloy, which includes anodic alloy dissolution in a pulsed mode, is proposed.Conclusions. Electrochemical dissolution of GS32-VI alloy under pulsed current action results in an optimal dissolution rate ratio of the alloy components, ensuring the production of a cathode precipitate with a total nickel and cobalt content of 97.5%.

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Mohamad Rashid, Nur Nadhirah, Harith Ahmad, Mohammad Faizal Ismail, et al. "Nanotubes in Chitin Mode Locker for Passive Mode−Locked Fibre Laser in 2.0 µm Region." Photonics 10, no. 3 (2023): 257. http://dx.doi.org/10.3390/photonics10030257.

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This research demonstrated an ultrafast passively mode-locked thulium-holmium doped fibre laser (THDFL) using a carbon nanotube (CNT)-chitin composite film as a saturable absorber (SA). The CNTs were fabricated using ultrasonic-assisted liquid-phase exfoliation, and the chitin biopolymer was derived from oyster mushrooms (Pleurotus Ostreatus). The free-standing SA successfully performed a mode-locking operation at a threshold input pump power of 203 mW with an operating wavelength of 1908.53 nm. The generated mode-locked pulses had repetition rate, pulse width, and signal-to-noise ratio (SNR) values of 16 MHz, 1.1 ps, and 69 dB, respectively. The work demonstrates the potential of CNTs embedded in chitin biopolymer as a sustainable and environmentally friendly SA for a wide range of applications, particularly for pulsed lasers.

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Anischenko I.V., Pokrovskii S.V., Osipov M.A., Abin D.A., Gritsaenko D. I., and Rudnev I. A. "Nonequilibrium states in the second-generation HTS composites under overcritical pulsed current impact." Technical Physics Letters 48, no. 13 (2022): 43. http://dx.doi.org/10.21883/tpl.2022.13.53352.18828.

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This paper presents the results of studying the processes of epy HTS composites switching from the superconducting to the resistive state at microsecond current pulses. Two modes of pulsed current load were used: with an amplitude of ~1.1Ic (the so-called "soft" mode) and with an amplitude of ~3Ic ("hard" mode). The possibility of passing supercritical currents through the tape without superconductor characteristics degradation is shown. To explain the processes occurring in the tape during the current pulse, 2D FEA (finite element analyzes) was developed, with the help of which the dynamic resistance of the HTS composite superconducting layer was calculated in the "hard" load mode and nonstationary processes of current redistribution between the different tape layers were demonstrated. Keywords: HTS composites, superconducting switch, nonequilibrium states, stable switching, irreversible switching.

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Tingting Lu, Tingting Lu, Juntao Wang Juntao Wang, Xiaolei Zhu Xiaolei Zhu, Ren Zhu Ren Zhu, Huaguo Zang Huaguo Zang, and Weibiao Chen Weibiao Chen. "Highly efficient single longitudinal mode-pulsed green laser." Chinese Optics Letters 11, no. 5 (2013): 051402–51404. http://dx.doi.org/10.3788/col201311.051402.

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Fischer, Baruch, Boris Vodonos, Shimie Atkins, and Alexander Bekker. "Dispersion-mode pulsed laser." Optics Letters 25, no. 10 (2000): 728. http://dx.doi.org/10.1364/ol.25.000728.

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Holzwarth, Michael J., Alexander M. Gigler, and Othmar Marti. "Digital Pulsed Force Mode." Imaging & Microscopy 8, no. 4 (2006): 37–38. http://dx.doi.org/10.1002/imic.200790065.

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Butylskii, Dmitrii, Ilya Moroz, Kseniya Tsygurina, and Semyon Mareev. "Effect of Surface Inhomogeneity of Ion-Exchange Membranes on the Mass Transfer Efficiency in Pulsed Electric Field Modes." Membranes 10, no. 3 (2020): 40. http://dx.doi.org/10.3390/membranes10030040.

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Despite the growing interest in pulsed electric field modes in membrane separation processes, there are currently not many works devoted to studying the effect of the surface properties and composition of ion-exchange membranes on their efficiency in these modes. In this paper, we have shown the effect of increasing mass transfer using different kinds of ion-exchange membranes (heterogeneous and homogeneous with smooth, undulated, and rough surfaces) during electrodialysis in the pulsed electric field modes at underlimiting and overlimiting currents. It was found that the maximum increment in the average current is achieved when the average potential corresponds to the right-hand edge of the limiting current plateau of the voltammetric curve, i.e., at the maximum resistance of the system in the DC mode. For the first time, the development of electroconvective vortices was visualized in pulsed electric field modes and it was experimentally shown that even at relatively low frequencies, a non-uniform concentration field is preserved at the time of a pause, which stimulates the rapid development of electroconvection when pulses are switched on again. In the case of relatively high pulse frequencies, the electroconvective vortices formed during a pulse lapse do not completely decay during a pause; they only slightly decrease in size.

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Анищенко, И. В., С. В. Покровский, М. А. Осипов, Д. А. Абин, Д. И. Грицаенко та И. А. Руднев. "Неравновесные состояния в ВТСП-композитах второго поколения при сверхкритических импульсных токовых воздействиях". Письма в журнал технической физики 47, № 19 (2021): 22. http://dx.doi.org/10.21883/pjtf.2021.19.51508.18828.

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This paper presents the results of studying the processes of еру HTS composites switching from the superconducting to the resistive state at microsecond current pulses. Two modes of pulsed current load were used: with an amplitude of ~ 1.1 Ic (the so-called "soft" mode) and with an amplitude of ~ 3 Ic ("hard" mode). The possibility of passing supercritical currents through the tape without superconductor characteristics degradation is shown. To explain the processes occurring in the tape during the current pulse, 2D FEA (finite element analyzes) was developed, with the help of which the dynamic resistance of the HTS composite superconducting layer was calculated in the "hard" load mode and nonstationary processes of current redistribution between the different tape layers were demonstrated.

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Guo, Silin, Yajun Lou, Cai Yue, Xinhai Zhang, and Fan Zhang. "Ultrafast Airy Beam Generation with a Mode-Locked Fiber Laser." Photonics 12, no. 1 (2024): 9. https://doi.org/10.3390/photonics12010009.

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We generate an ultrafast Airy beam with a mode-locked fiber laser. A diffractive optical element is placed inside the laser cavity and applies phase modulation on the pulses propagating in the cavity. The pulsed Airy beam is then obtained by Fourier transform of the first order diffracted beam of the diffractive optical element. The experimental results show that the beam profile and propagation characteristics of the laser pulses are consistent with the theoretical analysis. The pulsed Airy beam fiber laser we constructed has the advantages of compactness, easy integration, low cost, and high stability and robustness, which are of great significance for applications in industrial and other tough environments.

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Li, DongCheng. "Femtosecond pulsed laser technology and applications." Theoretical and Natural Science 28, no. 1 (2023): 166–73. http://dx.doi.org/10.54254/2753-8818/28/20230347.

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This paper describes femtosecond pulsed laser technology and related applications. The focus is on two core femtosecond pulsed laser technologies: femtosecond pulsed laser generation and amplification. In the generation of femtosecond pulsed lasers, mode-locking techniques, Kerr-lens mode-locking, and semiconductor saturable absorber mirrors are presented; in the amplification of femtosecond pulsed lasers, chirped-pulse amplification and coherent synthesis techniques are presented. This paper analyses the applications of femtosecond pulsed lasers in both the biomedical and manufacturing sectors and gives the development trends as well as the challenges of femtosecond laser technology. Femtosecond lasers are now used in a wide range of applications. Femtosecond pulsed lasers will develop in the directions of high power, miniaturisation, intelligence and precision. Laser tweezers will become the new direction of development in the future.

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Naidis, G. V., and N. Yu Babaeva. "Modeling of repetitively pulsed low-pressure CO₂ discharges." Physics of Plasmas 29, no. 4 (2022): 044501. http://dx.doi.org/10.1063/5.0087197.

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A model of repetitively pulsed low-pressure CO2 discharges is developed. In the framework of this model, plasma characteristics (electric field, electron density, gas temperature, and vibrational temperature of the asymmetric mode) are calculated both during the pulses and in the afterglow periods. The CO2 conversion factor in repetitively pulsed discharges is calculated. Results of computation of plasma parameters and of the conversion factor agree with available experimental data.

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Liu, Ching-Yao, Chih-Chiang Wu, Li-Chuan Tang, et al. "Design of High Peak Power Pulsed Laser Diode Driver." Photonics 9, no. 9 (2022): 652. http://dx.doi.org/10.3390/photonics9090652.

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This paper attempts to describe a laser diode driver circuit using the depletion mode gallium nitride high electron mobility transistor (D-mode GaN HEMT) to generate nanosecond pulses at a repetition rate up to 10 MHz from the vertical-cavity surface-emitting laser (VCSEL). The feature of this driver circuit is a large instantaneous laser power output designed in the most efficient way. The design specifications include a pulse duration between 10 ns and 100 ns and a peak power up to above 100 W. The pulsed laser diode driver uses the D-mode GaN HEMT, which has very small Coss difference between turn-on and turn-off states. The analysis is according to a laser diode model that is adjusted to match the VCSEL, made in National Yang Ming Chiao Tung University (NYCU). A design guide is summarized from the derivations and analysis of the proposed laser diode driver. According to the design guide, we selected the capacitor, resistor, and diode components to achieve 10 ns to 100 ns pulse duration for laser lighting. The experiment demonstrated that the maximum power-to-light efficiency can be as high as 86% and the maximum peak power can be 150 W, which matches the specifications of certain applications such as light detection and ranging (LiDAR).

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Kamynin, Vladimir, Vitalii Kashin, Dmitri Nikolaev, Anton Trikshev, and Vladimir Tsvetkov. "A Laser with Intracavity Spectral Beam Combining with Continuous-Wave and Pulse-Periodic Pumping of Various Lasing Channels." Photonics 10, no. 12 (2023): 1389. http://dx.doi.org/10.3390/photonics10121389.

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The output spectral, temporal, and spatial parameters of a two-channel Yb-fiber laser operating in an incoherent intracavity spectral beam-combining mode were investigated. One of the laser channels operated in continuous pumping mode, and the second channel operated in pulse-periodic pumping mode with a pulse duration of microseconds. When the channels operated separately, continuous lasing at a wavelength of λ1 was observed in one channel, and pulsed lasing at a wavelength of λ2 was observed in the other. When both channels operated simultaneously, it was shown that during the pump pulse action, the laser switched operation to pulsed collective mode lasing at a wavelength of (λ1 + λ2)/2. Lasing at wavelengths λ1 and λ2 was not observed at this time.

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Tan, Xin, Ya Liu, Yongkang Zheng, Zewu Xie, and Guoqing Hu. "Revealing the Evolution from Q-Switching to Mode-Locking in an Erbium-Doped Fiber Laser Using Tungsten Trioxide Saturable Absorber." Photonics 9, no. 12 (2022): 962. http://dx.doi.org/10.3390/photonics9120962.

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Passively Q-switching and mode-locking technologies can generate short pulses with durations that differ by several orders of magnitude widely used in different applications. Recently, Q-switching and mode-locking realized in an identical laser cavity with saturable absorbers was reported. The analysis of pulse conversion is helpful for us to further understand the pulse dynamics of a laser. In this paper, the pulse evolution from Q-switching, Q-switched mode-locking to mode-locking, is demonstrated by using a tungsten trioxide saturable absorber in a ring-cavity erbium-doped fiber laser. Firstly, self-started Q-switching at 1563 nm is observed, the repetition rate continuously increases, and the duration decreases when the pump power increased. Then, with an adjusting intra-cavity state of polarization under a high pump power level, stable Q-switched mode-locking pulses evolved from Q-switching, are observed. The amplitude of the emerged pulse sequence with a period of 36.8 ns, determined by cavity length, is modulated by the Q-switched envelope with the period of 10.3 μs. By optimizing the intracavity polarization carefully, stable continuous wave mode-locking operation is achieved eventually. To the best of our knowledge, this is the first experimental demonstration of Q-switching and mode-locking, respectively, in an identical transition-metal-oxides-based pulsed fiber laser without modification of cavity structure.

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Godun, D. V., S. V. Bordusau, and G. P. Budzko. "Output Current Control System of a High Voltage Electric Pulse Generator for Plasma Excitation." PLASMA PHYSICS AND TECHNOLOGY 6, no. 1 (2019): 7–9. http://dx.doi.org/10.14311/ppt.2019.1.7.

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A control and pulse discharge current limiting system integrated into an AC/DC converter and pulse modulator of a high voltage pulse generator have been developed. The peculiarity of such system\textquotesingle s operation is the stabilization of the power supplied to the discharge and the correction of the width of output electric pulses towards decrease upon reaching the specified pulsed current amplitude value. The system enables the pulse generator to work in the modes close to the ``short circuited load'' mode. In this case the driving module of a composite IGBT key performs the correction of the working pulse width and blocks the pulse generator operation if needed. The suggested circuit design solutions allow using the generator in a wide range of electric plasma-forming parameters' modes and working with various types of vacuum gas discharge systems.

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Ahmed, N., S. Omar, NF Zulkipli, et al. "The generation of nanosecond pulses at C-band region with titanium dioxide as a saturable absorber." Journal of Physics: Conference Series 2075, no. 1 (2021): 012013. http://dx.doi.org/10.1088/1742-6596/2075/1/012013.

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Abstract A passive mode-locked in an erbium-doped fiber laser with titanium dioxide (TiO2) film as a saturable absorber (SA) has been successfully demonstrated. The film is fabricated using a liquid phase exfoliation, which offers a simple and low-cost method. The self-starting mode-locked was created by inserting a 200-meter-long single-mode fiber into the laser cavity to balance the nonlinearity and dispersion of the cavity. The pulses operate stably at a central wavelength of 1560 nm. The pulse repetition rate was almost fixed at 988 kHz at a tuneable pump power from 145.83 mW to 187.04 mW. The repetition rate shows excellent stability with a signal-to-noise ratio (SNR) of 69 dB whilst the pulse width was virtually constant at 230 ns. The maximum output power was measured at 2.17 mW, eliciting maximum pulse energy of 2.19 nJ. This experiment demonstrates that stable mode-locked pulsed can be generated using TiO2-SA.

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Pudwat, S., P. Rakkwamsuk, and S. Damrongrattana. "Self-Cleaning Properties of TiO₂ Films Deposited by Reactive Magnetron Sputtering Using Smooth D.C. and Pulsed D.C. Source." Advanced Materials Research 55-57 (August 2008): 453–56. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.453.

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he TiO2 films were prepared by reactive smooth d.c. and pulsed d.c. magnetron sputtering on glass slide substrates. A metallic titanium target was reactively sputtered in a mixture of argon and oxygen. The influence of smooth d.c. and pulsed d.c. discharge power on films thickness, crystallinity, surface morphology, photocatalytic activity (methylene blue degradation) and hydrophilic activity were studied. At pulsed d.c. sputtering, plasma generator has been used to provide the asymmetric pulsed d.c. bias of the target at 100 kHz and pulsed off-time 4016ns. The structures of the films at 100nm and 300nm thick showed nano-grain size structure. The pulsed d.c. mode deposition exhibited a considerably lower surface roughness, but higher grain size compared to the films deposited with the smooth d.c. mode. At film thickness about 300 nm, the XRD peaks indicated that the dominant structure was anatase for which the preferred orientation was in (101) plane. It did not show any definite change of phase between the films deposited in the smooth d.c. mode and the film deposited in the pulse d.c. mode. For the photocatalytic activity, it was clearly seen that the films deposited by smooth d.c. mode showed a higher photocatalytic activity. The hydrophilic activity test, after the films had been irradiated by an ultraviolet light source for 30 min., the smooth d.c. mode films (thickness 300 nm) showed that a water contact angle can be less than 10°. In this study, the TiO2 films of smooth d.c. mode sputtering could be applied for a self-cleaning glass application.

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Ivankov, Anton S., Anastasia M. Kozhevnikova, Dmitry V. Schitz, and Igor V. Alekseenko. "Investigation of Nonthermal Plasma Jet Excitation Mode and Optical Assessment of Its Electron Concentration." Applied Sciences 11, no. 19 (2021): 9203. http://dx.doi.org/10.3390/app11199203.

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The results of a study of a plasma jet of atmospheric-pressure helium driven by a capacitive discharge using sine and pulsed modes of excitation are presented. The homogeneous discharge of a multi-channel plasma jet at gas temperature of 34 °C and helium flow rate of 0.5 L/min was achieved with short pulse excitation. A digital holography method is proposed to estimate a basic plasma parameter, i.e., its electron concentration. An automated digital holographic interferometry set-up for the observation and study of a nonthermal plasma jet in a pulse mode is developed and described. The synchronization features of recording devices with the generation of plasma pulses are considered. The electron concentration of the plasma jet is also estimated. The disadvantages of the proposed technique and its further application are discussed.

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Jiang Pei-heng, Shi Chao-du, Fu Shi-jie та ін. "130 μJ linear-polarized single-frequency 12-μm-core Er/Yb co-doped fiber amplifier based on pre-shaped seed pulse". Acta Physica Sinica 74, № 2 (2025): 0. https://doi.org/10.7498/aps.74.20241371.

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Stimulated Brillouin scattering (SBS) is the major barrier in the process of energy scaling for pulsed single-frequency fiber MOPA. Due to gain saturation effect, the laser pulse profile will be gradually distorted with the increase of pump power, which induces steep leading edge and narrower width for the amplified pulses. The resulting laser peak power would increase rapidly and thus the SBS threshold is reached earlier to limit the amplification of pulse energy.<br>A method to obtain high-energy pulsed single-frequency laser by pulse pre-shaping is demonstrated in this work. By designing the leading edge of the triangular pulse, optimizing its rising trend and the duration of the low-intensity rising part, the pulse width compression phenomenon caused by gain saturation has been alleviated effectively. Thereafter, the laser peak power increase process can be retarded to reach the SBS threshold such that higher energy can be amplified for the pulsed single-frequency fiber laser. In the experiment, when the seed pulse was optimized to a triangular profile with 401 ns of low-intensity rising part and 520 ns of pulse width, a 130.9 μJ linear-polarized pulsed single-frequency fiber laser was obtained in a 12-μm-core Er/Yb co-doped polarization-maintaining fiber. The pulse width was broadened to 608 ns at the maximum energy. Compared to the triangular pulse seed with a rapidly rising leading edge, the maximum energy has been increased around 25%. The optical signal-to-noise ratio and polarization extinction ratio were measured to be 42 dB and 16 dB at the maximum pulse energy, respectively. The corresponding spectral linewidth measured by delayed self-heterodyne system was 542 kHz. Higher pulse energy can be anticipated by further optimizing the pulse profile and using large-mode-are gain fibers.

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Афанасьєва, Ольга Валентинівна, Наталія Олексіївна Лалазарова та Олена Георгіївна Попова. "Нові технології лазерної поверхневої обробки". Aerospace technic and technology, № 2 (28 квітня 2021): 59–65. http://dx.doi.org/10.32620/aktt.2021.2.07.

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Subject and purpose. Currently, gas, solid-state, and fiber lasers are used to process materials in the aviation industry. For the thermal treatment of steels, gas CO2 lasers with a capacity of more than 1 kW used, which are reliable in operation but have high cost and low efficiency. There are no results on the use of low-power (up to 20 W) pulsed-mode lasers for surface hardening of steel products. The purpose of this work is to determine the modes of surface hardening of products from carbon and alloy steels using low-power solid-state pulsed YAG lasers. Methodology. For laser hardening, a 5 W solid-state YAG laser was used (diode pumping, radiation wavelength λ = 1,064 μm, pulse mode). The use of a nonlinear crystal made it possible to obtain UV radiation with λ = 0,355 μm (third harmonic). The following modes were investigated: processing with single pulses (duration 0,1...0,4 ms) and multi-pulse processing with short (30...70 ms) pulses. The scanning speed was 8...2 mm/s. The energy in the pulse was determined by the photoelectric method. Thermal hardening was performed on the following steels: У12, P6M5. The possibility of UV radiation hardening was evaluated on steel 20, 45, У12, and ШХ15. Findings. The optimum values of pulse duration for maximum hardness in laser hardening of the investigated steels. With multi-pulse treatment of steels, the pulse duration is shorter than with single-pulse treatment, the hardening intensity is higher, and the quality of the processed surface is better. Single-pulse and multi-pulse processing are accompanied by partial melting of the surface of steel products, which does not allow it to be used in cases where a high quality of the surface is required. Laser hardening of steel by ultraviolet radiation is not accompanied by melting. Conclusion. For surface hardening of products, where partial melting of the surface is possible, low-power lasers in pulse mode can be used. Laser hardening by ultraviolet radiation is a promising direction for thermal hardening of steels, which allows maintaining the original quality of the surface layer. Thermal hardening with low-power lasers can be effective for small-sized areas of the processed parts of the fuel equipment of aircraft engines, friction elements, and, especially, the tool is small.

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Hung, Tsung Pin, Chao Ming Hsu, Ah Der Lin, and Jao Hwa Kuang. "Residual Stress and Bead Profile Analysis of Pulsed Nd:YAG Laser Lap Welding." Applied Mechanics and Materials 284-287 (January 2013): 915–18. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.915.

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The weld bead temperature distribution and shape during pulsed Nd:YAG laser lap welding are studied. A volumetric heat source model is derived to include the surface flux and the keyhole heat transfer effects in the pulsed laser lap welding process. The proposed pulsed laser heat transfer mode is employed in a simulation with the commercial finite element software Marc. The numerically computed results of the weld pool dimensions are compared with the experimental results. The comparison shows a good agreement between the simulated and measurement results, indicating that the proposed model is feasible. The results reveal that the pulse duration and spot pitch have considerable influence on the temperature field distribution and the residual stress distribution.

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Yang, Li Jun, Xiao Liang Cheng, Gen Wang Wang, Qing Ming Xue, Ye Ding, and Yang Wang. "Experimental Evaluation of Cutting Quality of Carbon Fibre Reinforced Polymer with Pulsed Laser." Applied Mechanics and Materials 868 (July 2017): 172–77. http://dx.doi.org/10.4028/www.scientific.net/amm.868.172.

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To investigate the cutting quality of Carbon Fibre Reinforced Polymer (CFRP) with pulsed laser, experiments of high modulus CFRP were carried out using a Nd: YAG pulsed laser with wavelength of 1064nm. Experiments with five factors and five levels were designed to apply the response surface methodologies (RSM). The influence rule of processing parameters consisting scanning speed, pulse frequency, pulse energy, pulse duration and gas pressure on the morphology of machining region including the kerf width, kerf taper and the width of heat affected zone were studied, and the interactions of these input parameters on cutting qualities were also analyzed. Parameters optimization were conducted based on the mathematical model using the optimization software Design Expert. Verification experiments were carried out to prove the adequacy of the optimization results. The infrared laser with pulsed mode was found to be an effective method in processing high modulus CFRP.

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38

Saifutdinova, A. A., B. A. Timerkaev, and A. I. Saifutdinov. "Numerical study of transient processes in a corona dc microdischarge." Izvestiya vysshikh uchebnykh zavedenii. Fizika, no. 1 (2022): 143–55. http://dx.doi.org/10.17223/00213411/65/1/143.

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An extended fluid model is formulated that describes a corona microdischarge at atmospheric pressure in argon, taking into account the heating of the cathode-tip. Numerical calculations have been carried out, demonstrating two main modes of the negative corona: repetitively pulsed and glow discharge mode. For both modes, all the main parameters of the corona discharge plasma were obtained. It is shown that the appearance of Trichel pulses is in many respects similar to the transition from the Townsend to the glow discharge mode and is similar to self-oscillations manifested in a classical discharge with flat electrodes.

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Куропаткин, Ю. П., В. И. Нижегородцев, И. Н. Романов та ін. "Мобильный ускоритель на базе безжелезного импульсного бетатрона для радиографирования динамических объектов". Журнал технической физики 92, № 2 (2022): 297. http://dx.doi.org/10.21883/jtf.2022.02.52021.196-21.

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The paper concerns the mobile accelerator based on the ironless pulsed betaron. The accelerator is aimed to radiograph dynamic objects with a large optical thickness. It has a possibility to obtain up to three γ-pulses in one cycle of the acceleration. The accelerator operation description and results of its testing powering in a single-pulse mode are provided. The estimated boundary energy of an electron beam is equal to 60 MeV at the capacitance value of 1.8 mF of the storage of the betatron electromagnet pulsed power system. The thickness of the lead test object examined with γ-rays is 140 mm at 4 m from the tantalum target. The full width of the output γ-pulse at half maximum is equal to 120 ns. The dimension of the radiation source is 3×6 mm. The application of these accelerators within the radiographic complex will allow increasing the investigation efficiency due to the optimization of the hydrodynamic experiments geometry and the cost reduction.

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Laskovnev, A. P., M. I. Markevich, A. N. Malyshko, V. I. Zhuravleva, and A. M. Chaplanov. "Formation of colloidal solutions of silicon nanoparticles in ethyl alcohol with ultra-short laser pulses." Proceedings of the National Academy of Sciences of Belarus, Physical-Technical Series 66, no. 1 (2021): 7–11. http://dx.doi.org/10.29235/1561-8358-2021-66-1-7-11.

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The study of surface morphology of a silicon target after laser exposure, the formation and study of nanoparticles, obtained by laser ablation by ultrashort infrared pulses, were conducted. The material was processed using a yttrium aluminum garnet laser (LS-2134D) with a wavelength of 1064 nm, generating in a two-pulse mode (pulses are separated by a time interval of 3 μs, pulse duration is 10 ns, pulse repetition rate is 10 Hz, single pulse energy ~ 0.05 J). Alcohol solutions of silicon nanoparticles were obtained by laser ablation. It is shown that an ensemble of particles of different sizes (from 20 nm to 2.5 μm) is formed, which have no faceting. Using the method of scanning electron microscopy, the features of the morphology of the surface of the crater of polycrystalline silicon, which is in ethyl alcohol during pulsed laser processing in the double pulse mode, have been established. It is shown that the structure of the crater consists of silicon grains separated from each other by grooves; the material evaporates along the grain boundaries, and wide thermal etching grooves are formed. These results can be used to create solar cells.

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Braun, Edward. "Reducing Radiation Exposure in Lumbar Transforaminal Epidural Steroid Injections with Pulsed Fluoroscopy: A Randomized, Doubleblind, Controlled Clinical Trial." January 2018 1, no. 21;1 (2018): 53–60. http://dx.doi.org/10.36076/ppj.2018.1.53.

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Background: Fluoroscopy-guided lumbar transforaminal epidural steroid injections (L-TFESI) result in radiation exposure that carries risks to patients, physicians, and procedural staff. Objective: We aim to evaluate the feasibility of using pulsed fluoroscopy to safely reduce radiation exposure during L-TFESI. Study Design: This is a prospective, double-blind, randomized controlled trial. Setting: This study took place in a single-center, academic, outpatient interventional pain management clinic. Methods: Patients undergoing L-TFESI were randomly assigned to either continuous mode fluoroscopy (high-dose), pulsed fluoroscopy with 8 pulses per second (medium-dose), or pulsed fluoroscopy with one pulse per second (low-dose). Data on radiation doses and other clinical and demographic factors were also collected. Results: In total, 231 cases were analyzed in the high-dose group (n = 81), medium-dose group (n = 72), and low-dose group (n = 78). Mean radiation effective dose (µSv) was 121 in the highdose group, 57.9 in the medium-dose group, and 34.8 in the low-dose group (P < 0.001). The incidence of inadequate image quality in the pulsed groups was 6% (9/150). The body mass index (BMI, mean ± SD) was significantly higher in patients with inadequate image quality (37.3 ± 7.2) than with adequate quality (30.5 ± 7.2, P = 0.005). Limitations: Radiation doses were measured using the meter on C-arm fluoroscopes rather than by direct measurement. Conclusions: The use of pulsed fluoroscopy during L-TFESI resulted in radiation dose reduction of up to 72.1% without causing any significant adverse events. Pulsed fluoroscopy should be considered as an initial fluoroscopic setting for L-TFESI to reduce radiation exposure. Key words: Radiation, epidural, fluoroscopy, injection, exposure, pulse

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Rakhadilov, B. K., D. B. Buitkenov, M. Adilkhanova, Zh B. Sagdoldina, and Sh R. Kurbanbekov. "Influence of pulse plasma treatment on the phase composition and microhardness of detonation coatings based on Ti-Si-C." Bulletin of the Karaganda University. "Physics" Series 102, no. 2 (2021): 33–39. http://dx.doi.org/10.31489/2021ph2/33-39.

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The paper considers the study results of the phase composition and microhardness of detonation coatings based on Ti-Si-C after exposure to pulsed plasma treatment. The CCDS2000 detonation complex was used to obtain the coatings. Coatings surface modification was carried out using pulsed plasma exposure (PPE). The detonation coatings were treated with varying the distance H (30 mm mode 1, 40 mm mode 2, 50 mm mode 3) from the plasmatron to the hardened surface. It is shown that the treated coatings are generally characterized by high microhardness compared to the original coating. It was determined that after treatment by pulsed plasma effects an increase in the intensity of all reflexes phase Ti3SiC2 was observed, and the appearance of reflexes (101, 102, 112, 204, 0016) phase Ti3SiC2 was found, which indicates the increase of the content of Ti3SiC2 phase. The change in the fraction of phases indicates a solid-phase transformation during pulsed-plasma activation. High hardness is observed on the coating surface treated according to mode 3 (50 mm) and as it approaches the surface of the substrate modes 2 (40 mm) and 1 (30 mm) the hardness decreases. It is established that the increase in the microhardness of detonation coatings after pulse-plasma treatment is associated with an increase in the content of Ti3SiC2 phases in the coatings, as well as an increase in the defects density in the modified layer.

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Zhang, Qin, Wei Shi, Cheng Ma, and Lei Yang. "Evaluation of Pulsed Spark Discharge for Triggering GaAs Photoconductive Semiconductor Switches." Electronics 11, no. 18 (2022): 2954. http://dx.doi.org/10.3390/electronics11182954.

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In this study, a 3 mm gap GaAs photoconductive semiconductor switch (GaAs PCSS) was triggered by pulsed spark discharge. The typical linear mode of GaAs PCSS was fulfilled at a low bias voltage. The on-state current waveform was similar to that of an optical pulse. The “nonlinear mode” was demonstrated at a bias voltage of 4 kV; concurrently, the peak current and the carriers’ multiplication rate were 33 A and 179, respectively. This study indicates that pulsed spark discharge is a promising candidate light source for the direct triggering of GaAs PCSSs.

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Li, Zheng, Zhiwei Shi, and Hai Du. "Analytical Model: Characteristics of Nanosecond Pulsed Plasma Synthetic Jet Actuator in Multiple-Pulsed Mode." Advances in Applied Mathematics and Mechanics 9, no. 2 (2017): 439–62. http://dx.doi.org/10.4208/aamm.2015.m1297.

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AbstractMulti-field coupling simulation method based on the physical principles is used to simulate the discharge characteristics of nanosecond pulsed plasma synthetic jet actuator. Considering the effect of the energy transferring for air, the flow characteristics of nanosecond pulsed plasma synthetic jet actuator are simulated. The elastic heating sources and ion joule heating sources are the two main sources of energy. Through the collisions, the energy of ions is transferred to the neutral gas quickly. The flow characteristics of a series of blast waves and the synthetic jet which erupt from the plasma synthetic jet (PSJ) actuator are simulated. The blast wave not only promotes outward, but also accelerates the gas mixing the inhaled gas from the outside cavity with the residual gas inside the cavity. The performances of PSJ actuator fluctuate in the first three incentive cycles and become stable after that.

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Ahmad, Harith, Nur Atikah Azali, Leonard Bayang, and Norazriena Yusoff. "Generation of mode-locked thulium/holmium-doped fiber laser assisted by bismuthene/side polished fiber as saturable absorber." Laser Physics Letters 19, no. 7 (2022): 075103. http://dx.doi.org/10.1088/1612-202x/ac6804.

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Abstract An all-fiber passively mode-locked laser is demonstrated near the 2.0 µm wavelength region utilizing thulium/holmium-doped fiber as the gain medium and bismuthene/side-polished fiber (SPF) as saturable absorber (SA). The effect of bismuthene concentration on the performance of the generated mode-locked lasers has also been investigated. In this work, bismuthene was obtained by the exfoliation of bismuth under the ultrasonication technique. Two different concentrations of bismuthene (10 and 20 mg ml−1) were prepared to coat the SPF and be further used as SA. Based on the experimental results, the SA with 10 mg ml−1 concentration of bismuthene induced the most stable mode-locked pulses with good performance. The 10 mg ml−1 bismuthene/SPF SA produced pulses at the center wavelength of 1932.69 nm with the 3 dB bandwidth of 2.59 nm and a signal-to-noise ratio value of 63 dB. The generated pulsed laser exhibits pulse energy of 421.3 pJ, peak power of 261.4 W, and average output power of 4.613 mW. Overall, this work reveals the potential of bismuthene/SPF as an SA for generating mode-locked laser pulses, which is useful in photonics applications.

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Badziak, J., A. Dubicki, and R. Jarocki. "Short single-mode CO2 laser pulse generation by pulsed Q-switching." Optics & Laser Technology 25, no. 2 (1993): 133–37. http://dx.doi.org/10.1016/0030-3992(93)90109-s.

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Fei, Chen, Huo Yu-Jing, He Shu-Fang, and Feng Li-Chun. "Diode-Pumped Nanosecond Pulsed Laser with Pulse-Transmission-Mode Q -Switch." Chinese Physics Letters 18, no. 2 (2001): 228–29. http://dx.doi.org/10.1088/0256-307x/18/2/325.

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Brunel, Marc, Olivier Emile, Mehdi Alouini, Albert Le Floch, and Fabien Bretenaker. "Self-mode-locked pulsed monomode laser." Optics Letters 24, no. 4 (1999): 229. http://dx.doi.org/10.1364/ol.24.000229.

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van Zee, Roger D., Joseph T. Hodges, and J. Patrick Looney. "Pulsed, single-mode cavity ringdown spectroscopy." Applied Optics 38, no. 18 (1999): 3951. http://dx.doi.org/10.1364/ao.38.003951.

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Zaitsev, N. I., E. V. Ilyakov, S. V. Kuzikov, et al. "Pulsed high-order volume mode gyroklystron." Radiophysics and Quantum Electronics 48, no. 10-11 (2005): 737–40. http://dx.doi.org/10.1007/s11141-006-0002-8.

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Journal articles on the topic 'Pulsed mode'

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