- 标题
- 摘要
- 关键词
- 实验方案
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High Energy and Short Pulse Lasers || Phase Manipulation of Ultrashort Soft X-Ray Pulses by Reflective Gratings
摘要： In this chapter, we discuss the use of reflective diffraction gratings to manipulate the phase of ultrashort pulses in the extreme ultraviolet (XUV) and soft X-ray spectral regions. Gratings may be used to condition the spectral phase of ultrashort pulses, e.g., to compensate for the pulse chirp and compress the pulse, similarly to what is routinely realized for visible and infrared pulses. The chirped pulse amplification technique has been already proposed for soft X-ray free-electron laser radiation; however, it requires the use of a compressor to compensate for the pulse chirp and get closer to the Fourier limit. There are fundamental differences when operating the gratings at wavelengths shorter than ≈40 nm on a broad band: (a) the gratings are operated at grazing incidence; therefore, the optical design has to be consequently tailored to this peculiar geometry; (b) the grating efficiency is definitely lower; therefore, the number of diffractions has to be limited to two. We discuss the different configurations that can be applied to the realization of a grating stretcher/compressor.
关键词： extreme ultraviolet,soft X-ray optics,ultrafast optics,diffraction gratings,chirped pulse amplification
更新于2025-09-16 10:30:52
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Advances in Ultrafast Optics || 1. Ultrafast ultrahigh-intensity laser pulses
摘要： Generation of high intensity laser pulses has been regarded as one of the most important research topics since the invention of lasers. High intensity lasers are normally constructed using the master oscillator power amplifier (MOPA) configuration to boost the energy of short laser pulses. This configuration has been used in various locations such as the Shenguang facilities in China and the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in the USA; the latter is currently the largest laser facility in the world. This type of giant laser facility is usually employed for high-cost and large-scale scientific projects involving complex technology and only a few countries can perform this type of laser research. Because of the low repetition rate and long pulse duration of the achieved laser pulses, these laser facilities are not suitable for large-scale applied research. Furthermore, the output laser intensity is limited. For example NIF, constructed in 2009, includes 192 ultraviolet (UV) beams with the total energy up to 1.8 megajoules (MJ, 106 J). However, the peak power is only approximately 500 terawatts (TW; 1012 W) [1] because the pulse duration is at the nanosecond (ns; 10?9 s) level; the separation time between two pulses is as long as a few hours. At the other end of the scale, several research institutes have developed tabletop laser systems within regular-scale labs through the amplification of ultrashort-pulse lasers at the femtosecond (fs; 10?15 s) level. These lasers have peak powers at the petawatt (PW; 1015 W) level [2–4], a repetition rate of 1 hertz (Hz) [5], and a focus intensity reaching 1022 W/cm2 [6]. As a result of the 1991 discovery of the Kerr-lens mode-locking (KLM) phenomenon by the Sibbett group in the UK [7], along with the development of chirped pulse amplification (CPA) technology by the US-based Mourou group in 1985 [8], and research on ultrashort pulses, ultrahigh-intensity lasers have been advancing at an unprecedented pace since the late 1980s. New scientific records associated with significant breakthroughs have been made on a continuous basis. Ultrashort-pulse laser research has developed in two explorative directions. One path of development targets extremely short pulse duration promoted by mode-locking technology. Currently, laser pulse duration can reach the few-cycle level; in addition, attosecond (as; 10?18 s) laser pulses can be achieved using new physical mechanisms [9–11]. The second research trend is the ongoing extension of the laser peak power limit. An increasing number of femtosecond ultrahigh-intensity laser facilities with peak powers at the terawatt or even petawatt level have been developed [2–5], serving as powerful tools for in-depth research on ultrafast, ultrahigh-intensity laser pulses. Ultrashort pulses and ultrahigh-intensity laser technology are not only extensively employed in the fields of micromanufacturing [12–14] and medicine [15, 16] but have also been successfully and prominently implemented in various research areas, such as the exploration of atomic and molecular motion patterns [17, 18], laboratory simulations in astrophysics [19], and precision spectroscopy [20]. These applications have facilitated the emergence of many new subfields and groundbreaking scientific achievements. One of the two most representative events was the award of the 1999 Nobel Prize in Chemistry to the American researcher, Prof. A. H. Zewail. This prize was awarded for work on chemical kinetics using femtosecond laser pulses. The second representative achievement was the joint sharing of one half of the 2005 Nobel Prize in Physics by Profs. J. L. Hall and T. W. H?nsch; this prize was awarded for their achievements regarding the femtosecond laser frequency comb technique. With state-of-the-art features and innovative applications, ultrashort pulses, ultrahigh-intensity lasers have become crucial tools in the field of optical physics. Therefore, this chapter will first briefly review the essential technology and associated progress in research.
关键词： ultrahigh-intensity lasers,femtosecond lasers,laser technology,Kerr-lens mode-locking,petawatt lasers,optical physics,chirped pulse amplification,ultrafast lasers
更新于2025-09-16 10:30:52
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Fano resonance and amplification in a quadratically coupled optomechanical system with a Kerr medium
摘要： We discuss the Fano resonance and ampli?cation in a quadratically coupled optomechanical system with a nonlinear Kerr medium. We ?nd that effective cavity detuning and the strength of the Kerr nonlinearity lead to the appearance of the Fano resonance in the output probe ?eld at room temperature, respectively. We show that the Kerr nonlinearity causes the asymmetric line shape to appear in the intensities of the output Stokes ?eld and the second-order upper sideband generation. We also show that the Kerr nonlinearity can amplify the intensities of the output Stokes ?eld and the second-order upper sideband generation, and the ampli?cation factor is related to the strength of the Kerr nonlinearity. The ?ndings of this study have potential applications in optical switching and frequency conversion.
关键词： Fano resonance,quadratically coupled optomechanical system,amplification,Kerr medium
更新于2025-09-16 10:30:52
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Compression of laser pulses by near-forward Raman amplification in plasma
摘要： We propose a new scheme for compression of ultrashort laser pulses enabled by Near-Forward Raman Ampli?cation (NFRA) in plasma. In contrast to traditional forward Raman ampli?cation in plasma, the seed pulse in NFRA propagates faster than the pump through manipulation of the spatiotemporal properties of the pump beam. A “p-pulse” solution similar to that of stimulated Raman backscattering ampli?cation is obtained, indicating that NFRA can be used for compression of ultrashort laser pulses. NFRA is numerically demonstrated with a 2D simulation using a front-tilt near-forward pump pulse.
关键词： Raman amplification,plasma,laser pulses,pulse compression
更新于2025-09-16 10:30:52
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Numerical simulations to study turbulent magnetic field amplification by nonlinear interaction of high-power laser and kinetic Alfvén waves in laboratory and astrophysical plasmas
摘要： The model contouring the dynamics of transient nonlinear interaction between the high-frequency extraordinary-elliptically polarized laser (HFXPL) and low-frequency kinetic Alfvén wave (LFKAW) dynamics in the magnetized plasma is the focal point of the present investigation. The quasistatic ponderomotive force driven by the HFXPL pump induces density cavitation and humps in the low-frequency kinetic Alfvén wave. In order to study the intricate localized structures of HFXPL pump waves that evolve with time, the requisite dimensionless equations of the coupled system (HFXPL and LFKAW) are evaluated by using numerical methods in the nonlinear stage. The typical scale sizes of these structures in the early phase are ≈9 μm, and the typical time to grow is ≈10 ps. The ensemble-averaged magnetic power spectra are also presented, indicating energy cascade. The rendered investigations follow direct relevance to the experimental observations and are imperative in understanding turbulence in astrophysical scenarios.
关键词： kinetic Alfvén waves,high-power laser,astrophysical plasmas,laboratory plasmas,nonlinear interaction,turbulent magnetic field amplification
更新于2025-09-12 10:27:22
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Dual-mode detection of avian influenza virions (H9N2) by ICP-MS and fluorescence after quantum dot labeling with immuno-rolling circle amplification
摘要： Avian influenza virus (AIVs), hosted in poultry, are the pathogens of many poultry diseases and human infections, which bring huge losses to the poultry breeding industry and huge panic to society. Therefore, it is of great significance to establish accurate and sensitive detection methods for AIVs. In this work, a dual-mode detection method based on immuno-rolling circle amplification (immuno-RCA) and quantum dots (QDs) labeling for inductively coupled plasma mass spectrometry (ICP-MS) and fluorescence detection of H9N2 AIV was developed. The dual-mode detection of the QDs by ICP-MS and fluorescence is used to achieve mutual verification within the analysis results, thus improving the accuracy of the method. With the immuno-RCA, the sensitivity of the method was increased by two orders of magnitude. The limit of detection of the proposed method is 17 ng L-1 and 61 ng L-1, and the linear range of the proposed method is 0.05-5 ng mL-1 and 0.1-5 ng mL-1 with ICP-MS and fluorescence detection, respectively. The relative standard deviation (n=7) is 4.9% with ICP-MS detection and 3.1% with fluorescence detection. Furthermore, the proposed method was applied to the analysis of chicken serum samples, no significant different was found for two modes detection and the recoveries of the spiking experiments are acceptable, indicating that the method has good practical potential for real sample analysis.
关键词： ICP-MS,quantum dot,rolling circle amplification,H9N2 avian influenza virus,dual mode detection
更新于2025-09-12 10:27:22
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Attosecond Pulse Amplification in a Plasma-Based X-Ray Laser Dressed by an Infrared Laser Field
摘要： High-harmonic generation (HHG) of laser radiation has led to attosecond pulse formation which offers unprecedented temporal resolution in observing and controlling electron and nuclear dynamics. But the energy of attosecond pulses remains quite small, especially for photon energies exceeding 100 eV, which limits their practical applications. We propose a method for amplification of attosecond pulses in the active medium of a plasma-based x-ray laser dressed by a replica of the laser field used for HHG. The experimental implementation is suggested in hydrogenlike C5t x-ray laser at 3.4 nm wavelength in the “water window” range.
关键词： attosecond pulse amplification,infrared laser field,plasma-based x-ray laser,high-harmonic generation,water window
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Controllable Generation of Ultrashort Multi-Bound Solitons in a Mode-Locked Erbium-Doped Ring Laser with a Highly-Nonlinear Resonator
摘要： Mode-locked (ML) ultrashort pulse (USP) fiber lasers can be treated as an ideal platform to expand future applications due to a complex nonlinear dynamics with a presence of a high value of a group velocity dispersion and a third-order dispersion in the laser resonator. Up to now a series of novel ML regimes have been investigated e.g. self-similar pulses, noise-like pulses, multi-bound solitons, and a soliton rain generation. Multi-bound solitons (MBS) generation regime, also known as soliton molecules, is of considerable interest in various fields of applications. For example, the investigation of a MBS generation is very attractive for increasing the data transfer capacity in telecommunications due to coding alphabet extension. The coding concept of MBS suggests a data stream using more than two symbols (2?N symbols, where N is the number of generated solitons in a bound state) [1]. And also, recent research shows that using ultrafast bursts of pulses can improve the quality of laser ablation for medical applications [2]. Moreover, MBS generation can be also used in a coherent pulse staking amplification scheme increasing an amplification efficiency along with a formation of high-energy solitons at a high-repetition-rate [3]. Previously we have obtained a generation of stable low-noise ultrashort multi-bound solitons in a passive mode-locked all-fiber erbium-doped ring laser with a highly-nonlinear resonator [4]. Fig. 1 shows autocorrelation traces and spectrums of MBS generation obtained by pump power variation at a wavelength of 980 nm. The output spectrums are evidently showing high-contrast intensity fringes (up to ~20 dB) and autocorrelation traces having symmetrical form without additional intensity peaks that indicates a stable and strong coherent connection between ultrashort pulses and fixed coherent phase difference in the temporal domain between several identical pulses. It is known that the highest energy of a fundamental soliton in a laser resonator with duration τp is limited by the soliton area theorem Es ~ |β2|/(γ · τp), where γ is the net nonlinear coefficient and β2 is the total cavity dispersion [1]. Soliton energy quantization results in pulse splitting at operation powers higher than the fundamental limit. Here we experimentally demonstrate the formation multi-bound solitons with the controllable number of bound states 7 < N < 17 by pump power variation in the range from ~160 mW to ~377 mW obtained in a highly-nonlinear fiber ring cavity.
关键词： ultrashort pulse,laser ablation,fiber lasers,Mode-locked,coherent pulse staking amplification,soliton molecules,telecommunications,multi-bound solitons
更新于2025-09-12 10:27:22
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Tapered erbium-doped fibre laser system delivering 10 MW of peak power
摘要： We consider a fibre laser system generating ~10-mJ, ~500-fs pulses with a peak power of ~10 MW at a repetition rate of 100 kHz and emission wavelength of 1.56 mm. The system is based on a master oscillator – power amplifier configuration. The amplifier ensures chirped-pulse amplification. The pulses are then compressed by a dispersive grating compressor. The output amplifier stage is based on a specially designed tapered large mode area erbium-doped fibre for suppressing nonlinear effects. The experimental data agree with numerical simulation results for the stretcher, amplifier and compressor. The stretcher and amplifier have been simulated using a generalised nonlinear Schr?dinger equation. In addition, numerical simulation results suggest that optimising the stretcher and compressor will potentially allow the peak power of the system to be scaled up to ~30 MW.
关键词： erbium-doped fibre amplifiers,tapered fibre,dispersive grating compressor,high peak power fibre laser systems,chirped-pulse amplification
更新于2025-09-12 10:27:22
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Frequency modulation, amplification and compression of microwave pulses in a system with helically corrugated waveguides as a dispersive elements
摘要： We consider the possible implementations of the Chirped Pulse Amplification (CPA) technique widely used in optics for the microwave frequency band. We propose using helically-corrugated waveguides for pulse stretching and compressing as their dispersion properties strongly depend on geometrical parameters. For stretched pulse amplification, a helical-waveguide gyro-TWT can be used as a broadband amplifier. Simulations with parameters of the experimentally realized 30 GHz gyro-TWT show that for a 300 W, 200 ps incident pulse, amplification up to 6 MW can be achieved in this system, while in the linear regime of the same gyro-TWT the output power is only about 250 kW.
关键词： microwave pulses,gyro-TWT,Chirped Pulse Amplification,helically corrugated waveguides
更新于2025-09-12 10:27:22