Synchronous Pumping Research Articles

Machine Learning Surrogate Model Optimized by Improved Sparrow Search Algorithm for Multi-Objective Optimization of Permanent Magnet Synchronous Motor Direct-Drive Pump

Machine Learning Surrogate Model Optimized by Improved Sparrow Search Algorithm for Multi-Objective Optimization of Permanent Magnet Synchronous Motor Direct-Drive Pump

Spectrum Multiplexing of Multiwavelength Picosecond Oscillation of Synchronously Pumped Raman Laser Based on a Sr(MoO4)0.8(WO4)0.2 Crystal

Spectrum Multiplexing of Multiwavelength Picosecond Oscillation of Synchronously Pumped Raman Laser Based on a Sr(MoO4)0.8(WO4)0.2 Crystal

Mean-field equation for phase-modulated optical parametric oscillator

The widely established techniques for the generation of ultrashort optical pulses rely on passive mode locking of lasers, with the output pulse duration and emission spectrum determined by the intrinsic lifetime of laser transition in the gain medium. Due to the instantaneous nature of nonlinear gain, optical parametric oscillators (OPOs) are capable of generating optical radiation in all timescales from continuous-wave (cw) to ultrashort femtosecond regime, if driven by laser pump sources in the corresponding time domain. In the ultrashort timescale, operation of OPOs conventionally relies on mode-locked pump lasers, with the concomitant disadvantages of large footprint and high cost. At the same time, the lack of gain storage mandates the use of synchronous pumping, resulting in increased complexity. In this paper, we present the concept of phase-modulated OPO driven by cw pump laser. The approach overcomes the traditional drawbacks of ultrafast OPOs, enabling femtosecond pulse generation without the need for synchronous pumping, resulting in a simplified, compact, and cost-effective architecture using cw input pump lasers. We derive a mean-field equation for a degenerate χ(2) OPO driven by a cw laser with intracavity electro-optic modulator (EOM), and also including dispersion compensation. The equation predicts the formation of stable femtosecond pulses (<200fs), in both normal and anomalous dispersion regimes, with a controllable repetition rate determined by the frequency of the EOM. The remarkable functionality of the proposed scheme paves the way for the development of an alternative class of widely tunable coherent femtosecond light sources in both bulk and integrated format based on χ(2) OPOs using cw pump lasers. Published by the American Physical Society 2024

Deciphering the underlying mechanisms of the pharyngeal pumping motions in Caenorhabditis elegans

The pharynx of the nematode Caenorhabditis elegans is a neuromuscular organ that exhibits typical pumping motions, which result in the intake of food particles from the environment. In-depth inspection reveals slightly different dynamics at the various pharyngeal areas, rather than synchronous pumping motions of the whole organ, which are important for its effective functioning. While the different pumping dynamics are well characterized, the underlying mechanisms that generate them are not known. In this study, the C. elegans pharynx was modeled in a bottom-up fashion, including all of the underlying biological processes that lead to, and including, its end function, food intake. The mathematical modeling of all processes allowed performing comprehensive, quantitative analyses of the system as a whole. Our analyses provided detailed explanations for the various pumping dynamics generated at the different pharyngeal areas; a fine-resolution description of muscle dynamics, both between and within different pharyngeal areas; a quantitative assessment of the values of many parameters of the system that are unavailable in the literature; and support for a functional role of the marginal cells, which are currently assumed to mainly have a structural role in the pharynx. In addition, our model predicted that in tiny organisms such as C. elegans, the generation of long-lasting action potentials must involve ions other than calcium. Our study exemplifies the power of mathematical models, which allow a more accurate, higher-resolution inspection of the studied system, and an easier and faster execution of in silico experiments than feasible in the lab.

Numerical Study of the Scheme of a Fiber Optical Parametric Oscillator with Two-Arm Synchronous Pumping

Numerical Study of the Scheme of a Fiber Optical Parametric Oscillator with Two-Arm Synchronous Pumping

Coalescence characteristics of vibrated drops on a wettability gradient surface

The coalescence characteristics of two vibrated droplets at a certain distance on a microstructured surface with gradient wettability are investigated using a high-speed camera in this work. The results show that the volume ratio of the two droplets has a significant effect on the vibration modes. With the change in the volume ratio, the droplet exhibits different vibration modes, such as the pumping mode (PM), the rocking mode (RM) or the pumping–rocking mixed mode (PRM). In addition, the coalescence time of the two droplets varies with the volume ratio. When the volume ratio is close to 1, the two vibrated droplets are in synchronous PM and the coalescence time is the shortest. When the volume ratio is far from 1, the two droplets may show the RM, the asynchronous PM or the PRM. At this point, the coalescence time is increased, particularly for small volume ratios. Finally, the movement characteristics of three-phase contact lines are discussed, and a theoretical model is proposed to analyze the coalescence process. This work provides a new method to remove droplets rapidly, which is essential to enhance the heat-transfer performance of dropwise condensation.

Self-Separation of a Single Ultrashort Light Pulse in the Parametric Raman Anti-Stokes Laser Based on a CaMoO4 Crystal under Intracavity Synchronous Pumping

The effect of the self-separation of a single ultrashort light pulse of a parametric Raman CaMoO4 laser with birefringence phase matching under intracavity synchronous pumping by a mode-locked 1064 nm Nd:YAG laser is experimentally investigated and theoretically simulated. The conditions for the self-separation effect for the single ultrashort pulse at an anti-Stokes wavelength of 973 nm with the pulse duration of 9 ps and the pulse energy of up to 9 μJ are defined.

Spectrum multiplexing of multiwavelength picosecond oscillation of synchronously pumped Raman laser based on a Sr(MoO_4)-=SUB=-0.8-=/SUB=-(WO_4)-=SUB=-0.2-=/SUB=- crystal

For the first time to our knowledge, a single-phase solid solution Sr(MoO_4)0.8(WO_4)0.2 was used as an active medium of a Raman laser. Using the high-intensity synchronous picosecond pumping satisfying the condition of phase capture of the parametric Raman interaction on the second vibrational mode made it possible to oscillate six components of Raman radiation with a combined frequency shift on the first (888 cm-1) and second (327 cm-1) vibrational modes in the wavelength range of 1194-1396 nm. Oscillation efficiency of the multiwavelength Raman laser radiation was as high as 10%. By detuning the Raman laser cavity length, the pulse shortening down to 6 ps for the Raman laser radiation components with the combined frequency shift was obtained, which is an order of magnitude shorter than the pumping pulse duration (64 ps). Keywords: stimulated Raman scattering, single-phase solid solution, vibrational mode, synchronous pumping.

Обогащение спектра многоволновой пикосекундной генерации синхронно-накачиваемого ВКР-лазера на кристалле Sr(MoO_4)-=SUB=-0.8-=/SUB=-(WO_4)-=SUB=-0.2-=/SUB=-

For the first time to our knowledge, a single-phase solid solution Sr(MoO4)0.8(WO4)0.2 was used as an active medium of a Raman laser. Using the high-intensity synchronous picosecond pumping satisfying the condition of phase capture of the parametric Raman interaction on the second vibrational mode made it possible to oscillate six components of Raman radiation with a combined frequency shift on the first (888 cm–1) and second (327 cm–1) vibrational modes in the wavelength range of 1194-1396 nm. Oscillation efficiency of the multiwavelength Raman laser radiation was as high as 10%. By detuning the Raman laser cavity length, the pulse shortening down to 6 ps for the Raman laser radiation components with the combined frequency shift was obtained, which is an order of magnitude shorter than the pumping pulse duration (64 ps).

Nonlinear dynamic control of a photovoltaic pumping PMSM at MPP: Low-Frequency instability induced by Hopf bifurcation

ABSTRACT In a photovoltaic permanent magnet synchronous motor pumping system (PVPMSM), both photovoltaic modules and switching-mode converters present nonlinear and time-variant characteristics, which result in a difficult control problem. This paper presents an in-depth analysis of the operating point dynamics. A potential trade-off exists between maximum power and stability of the system operating point. Analysis of parametric singularities based on bifurcation theory permits to optimize the maximum power-stability trade-off. Tracing the bifurcation structures related to the parameter set (T, G), we can determine the maximum power point(MPP) in midway and far enough from the bifurcation points from these structures. An algorithm aiming to determine the MPP within the range of stability through power bifurcation analysis is proposed in this paper. Our methodology was validated with the simulation that was carried out on MATCONT/MATLAB, and the results are demonstrated.

Enhancing dissipative cat-state generation via nonequilibrium pump fields

Cat states, which were initially proposed to manifest macroscopic superpositions, play an outstanding role in fundamental aspects of quantum dynamics. In addition, they have potential applications in quantum computation and quantum sensing. However, cat states are vulnerable to dissipation, which puts the focus of cat-state generation on higher speed and increased robustness. Dissipative cat-state generation is a common approach based on the nonlinear coupling between a lossy pump field and a half-frequency signal field. In such an approach, the pump field is usually kept in equilibrium, which limits the cat-state generation. We show that the equilibrium requirement can be removed by leveraging a synchronous pump method. In this nonequilibrium regime, the speed of the cat-state generation can be increased by one order of magnitude, and the robustness to single-photon loss can be enhanced. The realization of synchronous pumps is discussed for both time-multiplexed systems and standing modes.

PMSM-Driven Solar Water Pumping System

In this paper the study describes a single-stage, self-contained solar photovoltaic (SPV) array-fed, permanent magnet synchronous motor water pumping system (PMSM). The two main contributions of this research are i) the development of a novel modified vector control (MVC) that improves the system's torque behaviour and (ii) the development of a special incremental conductance with variable step size (VSS-INC) with a stage technique that results in a rapid response. Maximum Power Point Tracking (MPPT) is offered, a DC-DC converter between stages is not required, and (iii) the system's overall response time under dynamic conditions is enhanced with the use of an SPV Power Feed Forward Term (FFT). A pump, a three-phase voltage source inverter (VSI), a PMSM, and an SPV array are among the parts of this system. Solar energy is transformed into electrical energy by the SPV array. The VSI performs the role of a power processing unit (PPU), supplying the necessary power to drive the PMSM. The motor-coupled pump completes the task of pumping water while the PMSM rotates. The provided empower system toolbox is used with MATLAB/Simulink to model and simulate this system.

Superhigh charge density and direct-current output in triboelectric nanogenerators via peak shifting modified charge pumping

Due to the great potentials in self-powered sensors and micro-nano power sources, triboelectric nanogenerator (TENG) has attracted numerous attentions. However, enhancing charge density and realizing direct-current (DC) are long-term significant issues for TENGs. In this work, we investigated a DC TENG with outstanding electricity generation characteristics based on quasi- synchronous double-stage self-charge pumping. The TENG works in a contact-separation mode with a four-layered parallel structure. The TENG possesses a high open-circuit voltage of 2300 V, a high short-circuit current of 3 mA, a high power of 150 mW and a superhigh transferred charge of 20 μC at 4 Hz, which are significantly enhanced from those in single-stage pumping and non pumped counterpart TENGs. The property-improving mechanism lies in that through the unidirectional self-charge pump with a slight time difference among TENGs, negative halves are moved to the adjacent positive halves, leads to the widening, higher and DC outputs at the final terminal, which employs the Plancherel theorem for peak shifting in framework of energy conservation law. The TENG can power light emitting diodes, electronic devices and an electrophoretic deposition of pigment coatings. This work provides a method for developing high-performance DC TENGs with superhigh transferred charge for various applications.

1.7 <bold>μ</bold>m self-synchronized picosecond pulsed random Raman fiber laser

Aiming at the structural complexity of the current 1.7 μm band short pulse lasers, we propose and implement a self-synchronized picosecond pulsed random Raman fiber laser. The half-open Raman cavity based on random distributed feedback is pumped by a 1 578 nm pulsed fiber laser to achieve a picosecond pulse output with a central wavelength of 1 695 nm and an average power of 224 mW. The composite cavity formed by distributed Rayleigh scattering automatically satisfies the synchronous pumping condition without the need for precise matching of cavity length or complex feedback control in the system. By inserting a wavelength division multiplexer in the cavity, the random sub-cavity noise is suppressed and the stability of the output pulse is improved. To the best of our knowledge, this is the first realization of a random pulse fiber laser operating at 1.7 μm, which can be widely used in bioimaging and material processing. <fig fig-type="abstract-image" id="F1" orientation="portrait" position="float"><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="1000-2618-2022-39-4-363/7A9ED982-4F80-49df-B290-3AA8759A767B-F001.jpg"/></fig>

A high frequency builder software for arbitrary radio frequency signals.

While the frequencies accessible by signal generators steadily rise, the synthesization of complex and arbitrary waveforms with high frequency components remains challenging, especially when restricted by an external reference clock. In this article, we present a comprehensive software package combined with state-of-the-art hardware as a solution for the generation of highly sampled, arbitrary radio frequency waveforms. The software can be used to conduct both synchronous and heterodyne pump-probe experiments due to a variety of different synchronization modules. While both kinds of modules allow for standard waveforms, such as sines, pulses, and bursts, as well as any arbitrary signal, the heterodyne modules additionally are not restricted by the reference clock frequency. Both the output and the synchronization module can be adapted to support additional measurement devices. Due to the modular software structure, individual classes can be exchanged while maintaining all functionalities. The software provides a user friendly graphical interface that allows us to compose, save, and load complex arbitrary waveforms within only a few steps. The frequency selectivity provided by the software-hardware combination allows us to directly target specific excitation states of physical systems. Conducting a heterodyne scanning transmission x-ray microscopy experiment, we are able to demonstrate the capabilities of the software when paired with a high sample rate arbitrary waveform generator. The heterodyne synchronization modules allow for unlimited flexibility leveraging arbitrary waveform generation to their full power. By solving the challenges of synthesizing highly complex electromagnetic waves, the software enables a large variety of experiments to be performed more conveniently.

Yb-Doped Fiber Chirped Pulse Amplification System Delivering 1 mJ, 231 fs at 1 kHz Repetition Rate

In this paper a single-channel chirped pulse amplification laser system based on Yb-doped photonic crystal fiber was constructed, which achieved a pulse energy output of 1 mJ with a beam quality close to the diffraction limit. Pulsed synchronous pumping was used to suppress amplified spontaneous emission at a repetition rate of 1 kHz. The de-chirped pulse width of 231 fs was achieved by precise systematic dispersion control, and the corresponding peak power reached 3.85 GW.

Stimulated Raman Scattering in Pb(MoO4)1−x(WO4)x with x = 0, 0.5, 0.8 and 1.0 with Combined Frequency Shifts on High- and Low-Frequency Raman Modes under Synchronous Picosecond Laser Pumping

Comparative characteristics of spontaneous and stimulated Raman scattering in Pb(MoO4)1−x(WO4)x single crystals (x = 0, 0.5, 0.8, and 1.0) including both the high (ν1) and low (ν2) frequency internal anionic group vibrations have been investigated. It was found that among these crystals, Pb(MoO4)0.2(WO4)0.8 is the most suitable for multi-wavelength Raman laser in several Raman modes simultaneously. This is caused by the optimal relative Mo/W content corresponding to the most efficient coherent combination of the (MoO4)2− and (WO4)2− vibrations enhancing the output radiation characteristics of the synchronously pumped Pb(MoO4)0.2(WO4)0.8 Raman laser. Oscillation of up to twelve, closely spaced SRS components in a range of 1128–1360 nm and the strongest pulse shortening down to 1.16 ps in comparison with not only PbMoO4 and PbWO4 but also with all the earlier investigated nominally pure scheelite-like tungstate and molybdate crystals has been achieved.

Raman dissipative solitons generation near 1.7 μm by synchronous pumping

Raman dissipative solitons generation near 1.7 μm by synchronous pumping

Numerical investigation of the fiber optic parametric oscillator scheme with a dual-arm synchronous pumping

Numerical investigation of the fiber optic parametric oscillator scheme with a dual-arm synchronous pumping

The Yb3+:LuAlO3 crystal as an active medium for picosecond mode-locked lasers

Herein, we report on the mathematical modelling and experimental study of the regime of nonsoliton mode locking in a laser based on the Yb3+:LuAlO3 (Yb:LuAP) crystal with longitudinal pumping by laser diode radiation. Simulation based on the Haus master equation permitted to determine the requirements for the parameters of a saturable absorber (SA), the level of the average output power, the size of the TEM00 mode of the cavity in the active element and on the gate to obtain a stable regime of generation of picosecond laser pulses. Laser experiments were carried out in a fourmirror X-shaped resonator using a semiconductor saturable mirror (SESAM) as a passive modulator and a laser diode with a fiber output of a maximum power up to 30 W at a wavelength of 978.5 nm as a pump source. We obtained a stable passive mode locking with a maximum average output power of up to 12 W and an ultrashort pulse duration of about 2 ps at an optical conversion efficiency of pump radiation into lasing radiation of about 38 %. Laser pulses were obtained at a central wavelength of about 999 nm with a minimum Stokes shift (about 2 %) with respect to the pump radiation, which significantly reduced the thermal load on the active element. Additionally, the preliminary results on the second harmonic generation and synchronous pumping of a parametric light generator using a Yb3+ : LuAlO3 crystal laser as a pump source are presented.